Sunday, 2 August 2015

Further comments on spinach and iron: part 2

For part one see here.

Who was Schupan?
Some "Schupan (1937)" has been indicated as the one who suggested that the ostensibly high iron content of spinach was due to an erroneously misplaced decimal point (see here). A researcher with that name publishing on spinach and iron during that time did not exist, however.

I was able to trace "Werner Schuphan" instead (mind the h after the p). While he did publish on all sorts of vegetables including spinach, I have not yet found the erroneous decimal point in his publications. Though my reading of Schuphan's publications is far from complete, the following from 1940 shows that he can hardly have claimed a misplaced decimal point in 1937: "Spinat zeichnet sich – wie wir sehenbesonders durch hohe Gehalte an Carotin, Chlorophyll, Eisen und Reineiweiß und Vitamin C aus." (Schuphan, W. 1940. "Über den Einfluss der Chlorid- und Sulfatdüngung auf Ertrag, Marktgängigkeit und biologischen Wert verschiedener Gemüse unter Berücksichtigung edaphischer und klimatischer Faktoren." Bodenkunde und Pflanzenernährung 19(5-6): 265-315). As the above quote reiterates the idea that spinach is rich in iron, it seems improbable that he had some years before spread the myth about a misplaced decimal point as the source for a falsely high iron content.

Schuphan is an interesting figure in the spinach legend for other reasons. Firstly, several of his publications suggest that spinach is rich in provitamin A, which makes him a potential source for Popeye's eating spinach for vitamin A (see here). Secondly, he published a study intended to show that the content of oxalic acid in spinach is unproblematic in 1958 (Schuphan and Weinmann: "Der Oxalsäuregehalt des Spinats." Qualitas Plantarum 5(1): 1-22). Thirdly, in 1965 he discovered that high incidences of methemoglobinaemia in babies around Hamburg, Kiel and Berlin was probably due to over-manuring spinach with nitrogen-fertilizer. A subsequent accumulation of nitrite from nitrate due either to false storage, processing or re-heating the prepared food lead to the poisoning, he suggested.

Now, I remember vividly how my parents and grandparents would always claim that the spinach mush must be eaten all up, for it cannot be re-heated. Parents always find creative was to turn scientific findings into the claim that the spinach must be eaten, it seems.

Friday, 31 July 2015

Further comments on spinach and iron: part 1

For an update on the thicket of myths around spinach and iron see here. Still, not everything about the spinach legend is clear yet.

[Update: A previous version of this post was itself unclear about Bunge's calculations. Corrected!] 

Wolff (1871)
The story begins with a collection of analyses of the compounds of ashes from various sources, including vegetables, published by Emil Theodor von Wolff in 1871: Aschen-Analysen von landwirthschaftlichen Producten, Fabrik-Abfällen und wildwachsenden Pflanzen. Berlin: Wiegand & Hempel.

Wolff (1871) gave the content of substances as portions of 100 parts of the pure ash. Pure ash, according to Wolff, is the raw ash minus the sand, coal and carbonic acid in it. Now that already gives me pause to wonder what coal and carbonic acid has to do in ash? I found no indication that the word "Asche" used to mean anything other than the remains of combustion. This coal-in-ash thing sounds like incomplete combustion to me. Anyway, the first of the "Bemerkungen" at page 1 of Wolff's publication is also important, because it explains that the amounts of raw or pure ash are again given as portions of 100 parts of dry matter unless otherwise mentioned.

As you can see from the table below (line 51 and 52), the portion of Fe2O3 in spinach was 2.1 or 4,6 parts respectively in 100 parts of pure ash. And the amount of pure ash was given as 16.27 or 16,70 respectively (of 100 parts of dry matter as the first of the Bemerkungen at page 1 explained). One could state it simpler by saying that the mass of the pure ash equalled 16.27% (or 16,7% respectively) of the mass of the dry matter and that the mass of the Fe2O3 equalled 2,1% (or 4,6% respectively) of the mass of the pure ash in turn.

Page 101 of Wolff (1871). My red underlining.












  
  
Bunge (1892)
Gustav von Bunge (1892. "Weitere Untersuchungen über die Aufnahme des Eisens in den Organismus des Säuglings." Zeitschrift für Physiologische Chemie 16:173-186)* said that he was prompted to measure the iron content of wild strawberries (footnote 2 at p. 180) and spinach (footnote 1 at p. 181), because of the strikingly high iron contents, which Wolff has given in his "Aschenanalysen" on the base of an analysis of Richardson. Bunge (1892, p. 181) concludes that Wolff's data is 15 times too high for strawberries and 16 times too high for spinach. Bunge's figure for the iron content in wild strawberries calculated from Wolff is rather illegible, but it should read 0.14 Fe in 100 dry berries (see below).  

[* Bunge was not really interested in the iron content of vegetables. His point of departure was the finding that the milk of mammals contained very little amounts of iron compounds, yet young mammals needed a lot of iron for the growing while suckling. The solution to this riddle was that mammals are born with a stock of iron compounds sufficient for the growing until they wean.]

Bunge (1892, footnotes at pp 180, 181). Footnote 2 from page 180 runs into page 181.
Bunge took Wolff's data and calculate the iron content in the dry matter of a vegetable by correcting the data for the oxygen from the air in the iron-oxide. His logic was as follows:
Weight of fresh vegetables → get rid of water through desiccation → weigh of dry vegetables → get rid of carbon, nitrogen, sulfur etc. (as gaseous oxides) but gain oxygen in iron oxide through combustion → calculate the sand, coal and carbonic acid out of the raw ash to get the mass of the pure ash → calculate the oxygen out of the mass of Fe2O3** → calculate the iron content of the dry mass from the thus corrected data.   
One caveat about this logic is that the pure ash will also have gained mass through oxygen from the air (e.g., in magnesia or calcium oxide). That is, the values for pure ash would also need to be corrected.

[** 30% of the mass of Fe2O3 stems from oxygen, which entered this product from the air during combustion. We know that from the atomic masses of Fe (55.85u) and O (16u). Hence 70% of the molecular mass of Fe2O3 (159.7u) stems from iron (55.85 times 2 = 111.7u) and 30% from oxygen (16u times 3 = 48u).]

Wolff's data for wild strawberries were 5.89 parts Fe2O3 in 100 parts pure ash and 3.40 parts pure ash in 100 parts dry matter (see data for Fragaria vesca in Wolff 1871, p. 127). Correcting these data for the fact that only 70% of the mass of iron oxide is from iron yields: 100 x 3.40% x 4.12% = 0.14 as stated in Bunge's footnote 2 at page 180 (see above, Bunge 1892, footnote 2, p. 180). Likewise, taking the higher value of Wolff's data on spinach, 4.60 parts Fe2O3 in 100 parts pure ash, and correcting for the oxygen in it yields: 100g x 16.70% x 3.22% = 0.54g. This corresponds to Bunge's statement that, according to one of the two analyses given in Wolff "100gr. der trockenen Blätter" would contain "einen halben Gramm Eisen" (see above, Bunge 1892, footnote 1, p. 181).

It is therefore likely that Bunge did just the same calculations as those done above. That is, Bunge multiplied the portion for iron (corrected) times the portion of pure ash (not corrected) times the 100 parts dry weight that Wolff started with. If, however, the portion of pure ash was not corrected for oxygen in compounds (for example, magnesia oxide), Bunge's calculations were necessarily too high.

Can we check how much he was too high? Yes! Look at line 52 in the table from Wolff reproduced above. Wolff gave portions for the following compounds: KO, NaO, CaO, MgO, Fe2O3, PO5, SO3, SiO2 and Cl. And the portions of these compounds add up to 101. That is, the pure ash was supposed to consist of these compounds and the sum is slightly higher than 100 due to rounding. Unfortunately, some of the chemical species given by Wolff do not exist. Potassium oxide comes as K2O, sodium oxide as Na2, phosphor oxide has several species (e.g., P4O6, P4O10) none of which corresponds to the one given by Wolff, sulfur trioxide is a gas, and Cl does not exist as such.

What a mess! Anyway, let's just take Wolff's chemical species for granted, even though we know better, and correct the portion of pure ash accordingly. The percentage of the mass that is due to oxygen in these compounds would be: 29% for KO, 41% for NaO, 29% for CaO, 40% for MgO, 30% for Fe2O3, 72% for PO5, 60% for SO3, 53% for SiO2 and 0% Cl. That yields the following corrected portions of these compounds: 6.88 for KO, 23.10 for NaO, 9.31 for CaO, 3.17 for MgO, 3.22 for Fe2O3, 3.34 for PO5, 3.72 for SO3, 1.49 for SiO2 and 0% Cl. That sums up to 54,14 meaning that 45.86% of the pure ash were made up of oxygen from the air. Hence the 16.70 parts pure ash given by Wolff (see line 52 in the table above) would reduce to 9.04 parts per 100 parts dry matter. The estimation of the iron content in 100g dry matter would go down to 0.29g. That is still high, but less so. Bunge (1892, p. 181, main text) found 0.0016g in 4.8893g dry matter equal to 0.0327g in 100g dry matter. Instead of being 15 times too high, the estimate from Wolff with corrected values would be roughly 9 times too high. 

The fault for the fact that Bunge thought Wolff's value for the iron content of spinach being 16 times too high is about 2/5 Bunge's (that's more than 1/3 but less than 1/2). Same should be true for the value for wild strawberries, which Bunge thought were 15 times too high. But I will leave the fun of doing the calculation to the reader. Get your PSE and go.

Another oddity, Bunge said that Wolff's data are based on an analysis of Richardson, but the citation that both Wolff (1871) and Bunge (1892) give for Richardson are false leads (see red underlined reference given by Wolff in the page reproduced above). Wolff's footnotes at the bottom of his tables give the water content of the vegetables in percent ("Proc."), which Wolff has collected from other sources. One of the sources that Wolff cited very often for these water contents is Richardson (1848), but I could not find it in the journal cited. The Annalen der Chemie und Pharmacie 67(3) of 1848, Justus Liebig's journal by the way, has no such publication from Richardson—and I neither found it in other volumes and issues around that time. 

My hunch is that the world of science was so small that authors could simply assume everybody knew who was meant and where to find it. In conclusion, the spinach-iron story as a mess from its very beginning.

Sunday, 21 June 2015

Cuvier's (1829) "living aggregate / agrégat vivant"

Some people think that "lving aggregate" is a phrase coined by Patrick Matthew (1831. On naval Timber and Arboriculture) and that later users must have taken it from him. Here's Fréderic Georges Cuvier in 1829 (Dictionnaire des sciences naturelles..., p. 81):
"Tout corps vivant a une existence bornée, qui commence à sa naissance et finit à sa mort, et dont la durée semble évidemment en rapport avec son organisation. Ce n'est d'abord qu'un germe ou qu'un abrégé de ce corps, qui se développe dans un être semblable à lui, et s'en détache pour avoir une existence individuelle et séparée, ou qui lui reste attaché, comme cela a lieu dans les plantes qui se multiplient par bourgeons et dans beaucoup de zoophytes, pour former un agrégat vivant."
"Every living body has a limited existence that begins at birth and ends at death, and whose duration seems obviously related to its organization. It is first a germ or an abridgment of this body that develops into a being similar to it and detaches to have an individual existenc,e and that remains separate or attached to it as is the case of plants that are propagated by buds and in many zoophytes to form a living aggregate." (my translation)

Friday, 19 June 2015

Lamarckisms in Naval Timber and Arboriculture (Matthew 1831)

Lamarck's theory of species transformation
Jean-Baptiste de Lamarck argued for the transformation of species from two principles. The first was that organisms change their habits in response to environmental changes, the second that these changed habits (use and disuse of organs) not only adapted the individual organism to the new circumstances within its life-time, but that through some physiological processes (fluids subtils) got permanent and heritable.
"Firstly, a number of known facts proves that the continued use of any organ leads to its development, strengthens it and even enlarges it, while permanent disuse of any organ is injurious to its development, causes it to deteriorate and ultimately disappear if the disuse continues for a long period through successive generations. Hence we may infer that when some change in the environment leads to a change of habit in some race of animals, the organs that are less used die away little by little, while those which are more used develop better, and acquire a vigour and size proportional to their use.
Secondly, when reflecting upon the power of the movement of the fluids in the very supple parts which contain them, I soon became convinced that, according as this movement is accelerated, the fluids modify the cellular tissue in which they move, open passages in them, form various canals, and finally create different organs, according to the state of he organisation in which they are placed. 
Arguing from these two principles, I looked upon it as certain that, firstly, the movement of the fluids within animals [...] and, secondly, the influence of the environment, in so far as animals are exposed to it in spreading throughout all habitable places, were the two general causes which have brought the various animals to the state in which we now see them." Lamarck (1809, translated by Elliot 1914, p. 2)
The one question that never occurred to Lamarck was a dichotomous one whether heritable variation was either due to environmental changes or to internal changes. In his theory changes of circumstances induced changes of habits, which induced changes of the constitution (through use and disuse of organs) of individuals in their life-time; and these did over the generations become heritable somehow (through fluids subtils). The following quote shows how he skated very close to the idea of natural selection, but then attributed the transformation to acquired modifications instead:
"Among individuals of the same species, some of which are continually well fed and in an environment [circonstances in original] favourable to their development, while others are in an opposite environment, there arises a difference in the state of the individuals which gradually becomes very remarkable. How many examples I might cite both in animals and plants which bear out the truth of this principle! Now if the environment remains constant, so that the condition of the ill-fed, suffering or sickly individuals becomes permanent, their internal organisation is ultimately modified, and these acquired modifications are preserved by reproduction among the individuals in question, and finally give rise to a race quite distinct from that in which the individuals have been continuously in an environment favourable to their development." (Lamarck 1809[1914], p. 108)
Lamarck never managed to get much of a reputation during his life-time and is remembered, rather, for getting it wrong. Buffon and Cuvier, the most famous biologists of his time, believed in the fixity of species. Consequently, Lamarck's views on species transformation were those of a pariah. His Philosophie Zoologique, for example, was only summarized and then summarily dismissed by Charles Lyell in his Principles of Geology (1830-33, vol. 2), it never got translated entirely until 1914. The translator, Hugh Elliot, narrates a memoir by François Arago of an event that illustrates Lamarck's underdog position within French science (Lamarck 1809[trans. 1914], preface, xxi).
     Napoleon received scientists and both Lamarck and Arago attended. Napoleon spoke to Arago first, but when Lamarck tried to give to Napoleon his newly finished Philosophie Zoologique, Napoleon rudely responded that he only accepts the book because of his earlier good work on natural history meaning systematics and classical morphological research probably of invertebrates:
     "What is this?" asked Napoleon. "Is it your absurd Météorologie with which you are disgracing your old age? Write on natural history, and I will accept your work with pleasure. This volume I only accept out of consideration for your gray hair. Here!" and he handed it to one of his aides. (Elliot 1914, xxi). Lamarck tried to explain that is was a work of natural history, but before he could finish, he burst into tears. In 1829 Lamarck died blind, embittered, and poor and was buried in an unmarked grave in Montparnasse, but a marginal note in the cemeteries register said "to the left of M. Dassas."  By the time of Lamarck's death, his theory of species transformation had been utterly rejected.

Matthew's theory of species transformation
Unlike Lamarck, Patrick Matthew (1831) located the origin of variation in sports that occurred spontaneously (as well as in hybridisation). He probably knew from his experience with growing fruit trees. In his view, the environmental factors were not the cause of variation, but the cause for selection among variants. That is, he proposed a new combination of two old ideas, that of natural selection and that of species transformation and, thereby, anticipated the theory of evolution through natural selection. He jeopardized his idea by couching it into Lamarckian terms, without ever citing Lamarck. I highlighted the terms that could have ticked his contemporaries off to dismiss his proposal as a mere warm-up of already refuted Lamarckian ideas in the following quote:
"As the field of existence is limited and pre-occupied, it is only the hardier, more robust, better suited to circumstance individuals, who are able to struggle forward to maturity, these inhabiting only the situations to which they have superior adaptation and greater power of occupancy than any other kind; the weaker, less circumstance-suited, being prematurely destroyed.
This circumstance-adaptive law, operating upon the slight but continued natural disposition to sport in the progeny (seedling variety), does not preclude the supposed
influence which volition or sensation may have over the configuration of the body. To examine into the disposition to sport in the progeny, even when there is only one parent, as in many vegetables, and to investigate how much variation is modified by the mind or nervous sensation of the parents, or of the living thing itself during its progress to maturity; how far it depends upon external circumstance, and how far on the will, irritability and muscular exertion, is open to examination and experiment. In the first place, we ought to investigate its dependency upon the preceding links of the particular
chain of life, variety being often merely types or approximations of former parentage; thence the variation of the family, as well as of the individual, must be embraced
by our experiments." Matthew (1831, 385f)
It seems likely that, mistaking Matthew's proposal for a mere warm-up of Lamarck's theory, many contemporaries thought it not worthwhile to test it, because they believed Lamarck to be already proven wrong by observations such as spontaneous sports or acquired modifications that were not inherited.

Sunday, 14 June 2015

Blyth's anticipation of natural selection (1835)

[For information on further anticipators visit: Natural Selection before Darwin and Wallace.] 

Blyth, Edward (1835) "An Attempt to classify the "Varieties" of Animals, with Observations on the marked Seasonal and other Changes which naturally take place in various British Species, and which do not constitute Varieties." The Magazine of Natural History 8: 40-46.
"It is a general law of nature for all creatures to propagate the like of themselves: and this extends even to the most trivial minutiae, to the slightest individual peculiarities; and thus, among ourselves, we see a family likeness transmitted from generation to generation. When two animals are matched together, each remarkable for a certain given peculiarity, no matter how trivial, there is also a decided tendency in nature for that peculiarity to increase; and if the produce of these animals be set apart, and only those in which the same peculiarity is most apparent, be selected to breed from, the next generation will possess it in a still more remarkable degree; and so on, till at length the variety I designate a breed, is formed, which may be very unlike the original type.
      The examples of this class of varieties must be too obvious to need specification: many of the varieties of cattle, and, in all probability, the greater number of those of domestic pigeons, have been generally brought about in this manner. It is worthy of remark, however, that the original and typical form of an animal is in great measure kept up by the same identical means by which a true breed is produced. The original form of a species is unquestionably better adapted to its natural habits than any modification of that form; and, as the sexual passions excite to rivalry and conflict, and the stronger must always prevail over the weaker, the latter, in a state of nature, is allowed but few opportunities of continuing its race. In a large herd of cattle, the strongest bull drives from him all the younger and weaker individuals of his own sex, and remains sole master of the herd; so that all the young which are produced must have had their origin from one which possessed the maximum of power and physical strength; and which, consequently, in the struggle for existence, was the best able to maintain his ground, and defend himself from every enemy. In like manner, among animals which procure their food by means of their agility, strength, or delicacy of sense, the one best organised must always obtain the greatest quantity; and must, therefore, become physically the strongest, and be thus enabled, by routing its opponents, to transmit its superior qualities to a greater number of offspring. The same law, therefore, which was intended by Providence to keep up the typical qualities of a species, can be easily converted by man into a means of raising different varieties; but it is also clear that, if man did not keep up these breeds by regulating the sexual intercourse, they would all naturally soon revert to the original type. Farther, it is only on this principle that we can satisfactorily account for the degenerating effects said to be produced by the much-censured practice of "breeding in and in." There would almost seem, in some species, to be a tendency, in every separate family, to some particular kind of deviation; which is only counteracted by the various crossings which, in a state of nature, must take place, and by the above-mentioned law, which causes each race to be chiefly propagated by the most typical and perfect individuals." Blyth (1835, 45f)

Friday, 12 June 2015

A.P. De Candolle's anticipation of natural selection (1820)

[For information on further anticipators visit: Natural Selection before Darwin and Wallace.]


In 1820 Augustin-Pyramus de Candolle (1778–1841) published his Essai élémentaire de Géographie Botanique. (Extrait du 18.e volume du Dictionnaire des sciences naturelles.) In it he wrote (p. 26):
"Toutes les plantes d'un pays, toutes celles d'un lieu donné, sont dans un état de guerre les unes relativement aux autres. Toutes sont douées de moyens de réproduction et de nutrition plus ou moins efficaces. Les premières qui s'établissent par hasard dans une localité donnée, tendent, par cela même qu'elles occupent l'espace, à en exclure les autres espèces: les plus grandes étouffent les plus petites; les plus vivaces remplacent celles dont la durée est plus courte; les plus fécondes s'emparent graduellement de l'espace que pourraient occuper celles qui se multiplient plus difficilement."

My translation:
"All the plants of a country, all those of a given location, are in a state of war with each other. All are equipped with means of reproduction and more or less effective nutrition. The first that establish themselves by chance in a given location, tend, by the mere fact that they occupy the ground, to exclude other species: the biggest stifle the smaller; the more perennial replace those with a shorter duration; the most fertile gradually seize the space that could otherwise be filled by slower multiplying ones."

By the way, Lyell also gave a translation in his Principles of Geology, Vol. 2, first published in 1832. As the first edition has not yet been digitized by any body, I'll give the passage from the second edition (p. 136f therein):
"Equilibrium in the number of species, how preserved.—'All the plants of a given country,' says De Gandolle, in his usual spirited style, 'are at war one with another. The first which establish themselves by chance in a particular spot, tend, by the mere occupancy of space, to exclude other species—the greater choke the smaller, the longest livers replace the replace those which last for a shorter period, the more prolific gradually make themselves masters of the ground, which species multiplying more slowly would otherwise fill.'"

By yet another way, Frank N. Egerton (2010. History of Ecological Sciences, Part 34: A Changing Economy of Nature. Bulletin of the Ecological Society of America 91:21–41. http://dx.doi.org/10.1890/0012-9623-91.1.21) also quoted Lyell's translation.

Friday, 29 May 2015

Erasmus Darwin (1818) on selection (sexual and natural)

[For information on further anticipators visit: Natural Selection before Darwin and Wallace.] 

Erasmus Darwin (1818. Zoonomia, vol. I, p. 396):

"The birds, which do not carry food to their young, and do not
therefore marry, are armed with spurs for the purpose of fighting
for the exclusive possession of the females, as cocks and quails.
It is certain that these weapons are not provided for their defence
against other adversaries, because the females of these species arc
without this armour. The final cause of this contest amongst the
males seems to be, that the strongest and most active animal should
propagate the species, which should thence become improved
.
       Another, great want consists in the means of procuring food,
which has diversified the forms of all species of animals. Thus
the nose of the swine has become hard for the purpose of turning
up the soil in search of insects and of roots. The trunk of the
elephant is an elongation of the nose for the purpose of pulling
down the branches of trees for his food, and for taking up water
without bending his knees. Beasts of prey have acquired strong
jaws or talons. Cattle have acquired a rough tongue and a
rough palate to pull off the blades of grass, as cows and sheep.
Some birds have acquired harder beaks to crack nuts, as the par-
rot. Others have acquired beaks adapted to break the harder
seeds, as sparrows. Others for the softer seeds of flowers, or the
buds of trees, as the finches. Other birds have acquired long
beaks to penetrate the moister soils in search of insects or roots,
as woodcocks; and others broad ones to filtrate the water of lakes,
and to retain aquatic insects, as ducks. All which seem to have
been gradually produced during many generations by the perpetual
endeavour of the creatures to supply the want of food, and to have
been delivered to their posterity with constant improvement of
them for the purposes required."

Thursday, 21 May 2015

...such collateral matter as...the question regarding species... (Matthew 1831)

Some plagiarism theorists try to argue that natural selection was the central theme of the book On Naval Timber and Arboriculture by Patrick Matthew (1831) and that the idea that it was a side issue that could easily be overlooked was a myth created by Charles Darwin, because he had plagiarised Matthew. Any scrap mentioning that the book contains ideas on species and varieties is taken as evidence that natural selection was central to On Naval Timber and could not be overlooked including what Matthew, speaking of himself in the third person, said in his preface: "The very great interest of the question regarding species, variety, habit, has perhaps led him a little too wide."
     However, in the very sentence preceding the one thus quoted, Matthew admits that it's a collateral issue put in only to spice up an otherwise insipid book on planting and timber. Here's the full passage (Matthew 1831, v-vi):
"It may be thought presumptuous in a person who has never had the curiosity to peruse the British classic authors on planting and timber—Evelyn, Hanbury, Marshall, Miller, Pontey—to make experiment of the public sufferance. The author does not, however, think any apology necessary; as, if the public lose time unprofitably over his pages, he considers the blame attachable to them, not to him. A writer does not obtrude as a speaker does, but merely places his thoughts within reach.
       As the subject [planting and timber], notwithstanding its great importance, might, per se, be felt dry and insipid by the general reader, accustomed to the luxuries of modern literature, the author has not scrupled to mix with it such collateral matter as he thought might serve to correct the aridity. The very great interest of the question regarding species, variety, habit, has perhaps led him a little too wide."

Thursday, 23 April 2015

Lamarck's analogy/homology of nature with culture (1809)

[For information on further anticipators visit: Natural Selection before Darwin and Wallace.] 


Types of comparison
Biologists distinguish analogous traits from homologous traits. Analogous traits are similar, because of convergent adaptation towards similar environmental conditions. An analysis of the fine structures of these traits, however, will show differences proving that they have been derived from different ancestral traits. The similarity is only superficial. The eyes of vertebrates and octopuses often serve as an example of analogous traits. Although they look extremely similar, superficially, analysing the fine structure reveals, for example, that the innervation of the retina is inverse in vertebrates, but not in octopuses.  
      Homologous traits can look similar or different, depending on the similarity or difference in environmental conditions to which they have been adapted. An analysis of their fine structure, however, will show identities proving that they have been derived from the same ancestral trait. The standard example for homologous traits are the limbs of vertebrates. Although they can look as different (divergent) as the wings of bats and birds or the legs of horses and humans, the fine structure (of bones, tendons, muscles) reveals that they have been derived from the same ancestral limb.
     With this distinction, we can categorise comparisons as follows. If a comparison highlights differences in effects but does not compare the underlying causes, it will be a superficial contrast. If it highlights similarities in effects but does not compare the underlying causes, it will be a superficial analogy. If it highlights similarities in effects but also shows that these are due to the different underlying causes, it will be a deep analogy. Finally, if effects are similar or divergent, but the underlying causal machineries are identical, it will be a homology.

Categories of comparisons

superficial analogy deep analogy superficial
contrast
homology

effects

similar


similar


different

similar
or divergent

causes

--

different


--


identic
"--" means that the causal relations are not being compared.

Lamarck's homology
As shown in the previous post, Charles Naudin proposed that natural and artificial selection were not only superficially similar (analogous) in their effects, but also that this similarity was due to homologous causes. Alfred Wallace and Charles Darwin had not yet published and Matthew (1831. On Naval Timber and Arboriculture) had proposed a difference and conflict in the effects of of natural and artificial selection and did not explicitly compare the causal machineries of both processes (see taxonomy of comparisons below). Matthew's proposal was either a superficial contrast or an implied homology with divergent effects. That is, even as a homology, it was different from Naudin's homology of causes with similar effects. Therefore, Matthew (1831) is an unlikely source of inspiration for Naudin's proposal. But Lamarck (1809. Philosophie Zoologique) explicitly proposed a similarity of the effects of nature and culture due to homologous causes.

Ironically, the first English translation of Lamarck's Zoological Philosophy that is digitised and available online (via Archive.org, but not via books.google) is that of Hugh Elliot from 1914. Therefore, books.google will generally fail to identify Lamarck as a possible source of inspiration for English literature. 

For simplicity (and sparing the reader the pleasure of my translations from French into English), I will quote from the translation of Elliot. As Lamarck did not publish later editions of his Philosopie Zoologique that could have differed from his first, taking Elliot's translation is just as well as translating from the French would have been. 

The homology between nature and culture is at page 109 of Elliot's translation. The passage begins with a Buffonism:     
"Those who have observed much and studied large collections, have acquired the conviction that according as changes occur in environment, situation, climate, food, habits of life, etc., corresponding changes in the animals likewise occur in size shape, proportions of the parts, colour, consistency, swiftness and skill.
What nature does in the course of long periods we do every day when we suddenly change the environment in which some species of living plant is situated."
The original passage is at page 225-26 of Lamarck (1809, vol. 1):
"Ceux qui ont beaucoup observé, et qui ont consulté les grandes collections, ont pu se convaincre qu'à mesure que les circonstances d'habitation, d'exposition, de climat, de nourriture, d'habitude de vivre, etc., viennent à changer; les caractères de taille, de forme, de proportion entre les parties, de couleur, de consistance, d'agilité et d'industrie pour les animaux, changent proportionnellement.
Ce que la nature fait avec beaucoup de temps, nous le faisons tous les jours, en changeant nous-mêmes subitement, par rapport à un végétal vivant, les circonstances dans lesquelles lui et tous les individus de son espèce se rencontroient."

Conclusion
In contrast to later comparisons of natural with artificial selection, Lamarck had use-inheritance in place of selection. Charles Naudin merely recombined the strong homology claim already present in French science with the also already present idea of selection (see previous post).

Saturday, 18 April 2015

Naudin's analogy/homology of natural and artificial selection (1852)

[For information on further anticipators visit: Natural Selection before Darwin and Wallace.] 

Types of comparison
Biologists distinguish analogous traits from homologous traits. Analogous traits are similar, because of convergent adaptation towards similar environmental conditions. An analysis of the fine structures of these traits, however, will show differences proving that they have been derived from different ancestral traits. The similarity is only superficial. The eyes of vertebrates and octopuses often serve as an example of analogous traits. Although they look extremely similar, superficially, analysing the fine structure reveals, for example, that the innervation of the retina is inverse in vertebrates, but not in octopuses.  
      Homologous traits can look similar or different, depending on the similarity or difference in environmental conditions to which they have been adapted. An analysis of their fine structure, however, will show identities proving that they have been derived from the same ancestral trait. The standard example for homologous traits are the limbs of vertebrates. Although they can look as different (divergent) as the wings of bats and birds or the legs of horses and humans, the fine structure (of bones, tendons, muscles) reveals that they have been derived from the same ancestral limb.
     With this distinction, we can categorise comparisons as follows. If a comparison highlights differences in effects but does not compare the underlying causes, it will be a superficial contrast. If it highlights similarities in effects but does not compare the underlying causes, it will be a superficial analogy. If it highlights similarities in effects but also shows that these are due to the different underlying causes, it will be a deep analogy. Finally, if effects are similar or divergent, but the underlying causal machineries are identical, it will be a homology.

Categories of comparisons

superficial analogy deep analogy superficial
contrast
homology

effects

similar


similar


different

similar
or divergent

causes

--

different


--


identic
"--" means that the causal relations are not being compared.

M. L. Vilmorin's contrast
The house of Levêque de Vilmorin is a famous family of botanists, seed dealers and breeders (note: one French synonym for breeder is "sélectionneur"). Its history reaches back to the Parisian seed store of Claude Geoffroy and her husband Pierre Andrieux, who were the chief seed suppliers for king Louis XV. Their daughter, Jeanne Marie Adélaïde Andrieux (1756-1836), married Philippe Victoire Levêque de Vilmorin (1746-1804). They created the Vilmorin-Andrieux house (1775), which grew into the Vilmorin-Andrieux company (1815). Today Vilmorin & Cie is, according to its own website, the fourth biggest seed producer in the world.

At 6 January 1847, M. Trochu wrote a letter to L. Vilmorin, describing his experiments in trying to fix a variety of Gorse without thorns, which he had found near his house. He Failed but inspired M.L. Vilmorin to write an article in turn (Vilmorin, M.L. 1851. "Notes sur un projet d'exprérience ayant pour but de créer une variété d'ajonc sans épines se reproduisant par graines; par M. L. Vilmorin, membre correspondant de la Société Industrielle, à Paris. Bulletin de la Société Industrielle d'Angers 22: pp. 253-261).

After describing the efforts of his colleague, Vilmorin speculates about species and varieties, about the forces that keep the species fixed in nature, and of the spectre of breeding and fixing new varieties. Vilmorin thought that a balance of forces prevailed in nature keeping the species close to its type, but that humans could upset this balance in favour of the force that pulled varieties away from the type. He therefore thought of these two forces as a centripetal and a centrifugal one pulling away or towards the type respectively. He also referred to these "forces" as "laws," calling the centripetal one the law of atavism (or similarity to species type) and the centrifugal one the law of individual variation or idiosyncrasy. Here's my translation: 
"From what we know about the power of nature in the law of individual variations, it must look very likely that there exists on the extent of the Bretagne any number of Gorse individuals without thorns in the middle of an immense number of thorny individuals. However, it is sufficient that one of these individuals to print direct descent from seed a little more pronounced character, and as any part of its products were unarmed like him, that it was then possible to arrive quickly enough by a well-understood selection, completely free the new breed. But if we think that individuals more or less devoid of thorns which were met so far were from thorny parents, we will conceive the chance to get spineless relatives of products that are likewise is necessarily slightly larger, and that this opportunity will increase as the number of successive generations will grow for the modified plant.
     If we consider a seed when planted and will create a new individual, we can look at it as attracting two distinct and opposing forces, regarding the characters that will present the plant that must be born. These two forces, which act in the opposite direction and balance each other results in the fixity of species that can be considered as follows: The first, or centripetal force, is the result of the law of similarity for children to fathers, or atavism; its action results in maintaining the species within the assigned limits of variation, while the differences is produced by the opposing force.
     The former, or centrifugal force, resulting from the law of idiosyncrasy that each individual in a species, although it may be supposed born of an individual (or couple), features unique differences that constitute its own physiognomy and produce the infinite variety in unity that characterizes the works of the Creator.  
     For simplicity, we first consider atavism as constituting a single force; but if you think about it, we will see that it is rather a bundle of forces acting approximately in the same direction and is composed of the individual attraction of all ancestors. In order to facilitate the understanding of the action of this force, however, we first have to abstractly consider the force of similarity in/as the mass of ancestors, which can be considered to constitute the attraction of the species type, and to which we will reserve the name of atavism; then separately and in a more special way, the attraction or force of similarity to the direct father, which, less powerful but closer, tends to perpetuate in the child the proper characters of the immediate parent.  
     As long as the father is not appreciable far from the type of the species, these two forces act in parallel and blend, and changes that may occur in this case, by virtue of the law of idiosyncrasy, may occur in all directions without altering any particular. It is no longer so if the direct parent is significantly distant from the species type; the force of similarity to the direct parent now combines with the one of individual variation leading to excessive deviation in the direction of the resultant of the two forces, or, if one prefers, the new changes then radiate, not around the species type as center, but around a point placed on the line, which separates the type from the first deviation [variant] obtained.  
     Abandoned to nature, individual variants almost always die in the overflowing mass of individuals that it [nature] sacrifices continually. Hence the fixity of natural species. But obtained by humans, these variations are protected; their descendants multiply; while obeying the more complex laws governing now, they produce the many changes he was able to fix for his use. It was then also the influence of man, choosing to multiply through offspring only the modified individuals, counterbalancing, by constant efforts, the constant force of atavism, and comes to free or fix the modified races." (p. 255-257)
We can here see a specimen of a what might be called a physicalistic 'force paradigm.' Herbert Spencer' Synthetic Philosophy also had many pairs of forces keeping each other in moving equilibria (see here). In Vilmorin's case, these forces are called Atavism and Idiosyncrasy (the law of individual variations). After these pseudo-Newtonian speculations about pseudo-forces, however, he arrived at the insight that artificial selection can transform species (see quote above). 
     That is, humans can protect variants or sports from nature that would otherwise eliminate them. As Vilmorin also thinks that more complex laws are governing under the human regime than under nature, he sees a contrast between artificial and natural selection, not an analogy or homology.

Naudin's homology
A reprint of Vilmorin's article (Vilmorin, L. 1852. "Ajonc sans épines1. Notes sur un projet d'expérience ayant pur but de créer une race d'Ajonc sans épines se reproduisant de graines." Revue Horticole, Ser. 4, Tome 1: 22-29 [the footnote (1) in the title states that this article is an extract from the earlier one]) inspired Charles Naudin (1852 Considérations philosophiques sur l'espéce et al variété. Revue Horticole, Ser. 4, Tome 1: 102-109) to ponder the species problem in turn. He opened as follows:
"No doubt, the readers of the Revue Horticole have read with interest, in the issue of January 16, an article of M. L. Vilmorin about a variélé of thornless Gorse, whose fixation would be of great importance for agriculture, where this clever experimenter develops a theory already confirmed by the experience of the possibility of creating, in species such as nature provides us with, varieties, races, or even new artificial species most directly relevant to our needs. This theory, we say, is confirmed by experience; strictly speaking, it is a statement of the methods used empirically for centuries, and those used today by horticulturists almost instinctively, and without really realizing it, to obtain new varieties in useful and ornamental species that are introduced every day in our gardens." (p. 102f)
Unlike Vilmorin, Naudin saw natural and artificial selection as homologous in their causal machinery a with similar effects:
"We do not think that Nature has made its species in a different fashion from that in which we proceed ourselves in order to make our varieties; or better, we carried it's [Nature's] process into our practice." (p. 104)

"Such is, in our ideas, the course followed by nature; like us, it wanted to form races appropriate for their needs; and with a relatively small number of primordial kinds, she gave birth in succession and at various times, to all plant and animal species that inhabit the globe." (p. 104)

"Nature has operated on an immense scale and with immense resources; we, on the contrary, we do so with extremely limited means; but between its processes and ours, between his results and those we get, the difference is in any amount; between its species and those we create, there are only the more and less." 
Naudin even mentions Lamarck, praises and criticises him, and improves his scala naturae into a tree of life (p. 105f). Thereafter follows a long discussion of the implications for classification.

Conclusion
Now, Wallace and Darwin had not yet published and it is highly unlikely that the French horticulturist Naudin had read the book On Naval Timber and Arboriculture by Matthew (1831). Furthermore, Naudin's comparison observes that the effects of natural and artificial selection are similar and claims that this is due to a homology of the causal relations underlying both processes. Matthew (1831), on the other hand, observed that effects of natural and artificial selection are in conflict with each other and did not explicitly compare the causal machineries of both processes. His proposal is either a superficial contrast or an implied homology of causes with divergent effects.
      Therefore, it is more likely that Naudin's inspiration for the strong homology with similar effects came from Lamarck's observation that nature and culture had similar effects that were due to homologous causes (see next post).