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.