Updated 12.03.2015: Loudon's Treatise came in two volumes. Interesting passages from volume 1 are added. 13.03.2015: Added a natural theology statement of Loudon (1806, Vol. 1, p. 192). 15.03.2015: Further relevant passages on the effects of culture on plants.]
Some folks believe that Charles Darwin and Alfred Wallace plagiarised Patrick Matthew, because the latter formulated the idea that species may be transformed by natural selection already in 1831 in his book On Naval Timber and Arboriculture.
Matthew (1831) also criticised the works of other scholars of arboriculture without making bones about it. In one case, however, he packaged his criticism of John Claudius Loudon in the form of criticising a long quote by Henry Steuart of Loudon (1806. A treatise of forming, improving, and managing country residences. Vol 2, pp. 502-505). Matthew introduced his re-quote and criticism of this passage as follows (for the sake of contrast to quotes Matthew gets a different font):
"We shall finish our remarks on Sir Henry's work by making some observations upon a quotation made by Sir Henry Steuart from A Treatise on the Forming and Improving of Country Residences by the Author of the Encyclopaedia of Gardening etc.— an author who combines talent successful industry and enlightened benevolence in no common degree We are sorry to appear before this author whom we have long esteemed in opposition yet we regret the less as we consider him one of the few who prefer accuracy and truth to an old opinion and whose name stands too high to be affected by a casual misconception." (Matthew 1831, p. 295)As you can see, Matthew refers to the "Author of the Encyclopaedia of Gardening" rather than simply giving his name, Loudon. This is quite strange, because Matthew was, otherwise, very outspoken and did not fear to openly criticise other scholars. In a previous post, I have already shown the further peculiarity that Matthew did not transport all the changes, which Steuart has taken the liberty to introduce into his quotation of Loudon. Sometimes Matthew reverted to the original usage of Loudon. This suggests that Matthew's re-quote was a dummy, and that Matthew did have Loudon's original at his disposal.
Anyway, let's see what Matthew might have found, if he had checked Loudon's original.
1. Loudon's Treatise of 1806Volume 1
Loudon first defines the properties of vegetables in an ecological manner and then claims that one can predict the nature of soils from the environmental 'properties' (or requirements) of the plants naturally growing in them (my highlights):
"3. The Properties of Vegetables.—By this is meant their place of growth, their natural soil, exposure, climate, longevity, time of flowering, &c. It is discovered by observation, and ought to be recorded in all complete descriptions of vegetables. It is of great utility to agriculturists, by enabling them to adopt proper modes of cultivating useful plants, or destroying pernicious ones, and also to discover the soils and plants reciprocally adapted to each other." Loudon (1806, Vol. 1, p. 189).
"With respect to discovering the nature of soils by the properties of plants, it can be done with greater certainty by this than by any other branch of science." Loudon (1806, Vol. 1, p. 190)He then continues to give examples of plants that indicate wet soils, frequent flooding and other things related to soils.
On the occasion of writing about animals in agriculture, a statement revealing his natural theology slips in, odd though it is, as it also reveals that he regards humans as animals:
"Even a very slight general knowledge of the human frame will excite our wonder and awe at the contrivance of the whole, and confirm and establish the mind in the natural sentiment of Deity." Loudon (1806, Vol. 1, p. 192)Later he expands the idea of an ecological correlation between soils and plants to suggest a similar correlation between, say, plants and insect species or even races of man and regions of the globe. Without Whiggish retrospective, this passage simply stands as an observation about the natural assembly of plants and animals, that may have inspired scientifically minded readers to get all sorts of ecological ideas, but likewise may have inspired faithful readers to wax about providence. We cannot tell, but have to record the predecessors:
"The arrangement universal in nature is what will be most pleasing to general admirers. Its principles are perfectly simple; being nothing more than this, "that one kind of objects, beauties, or characters, always prevails in one place; and that when another succeeds, it is generally done in a gradual manner, the interval between them being composed of characters or beauties irregularly blended together." This is beautifully illustrated throughout all nature, whether animal, vegetable, or mineral. It may be observed, as I shall afterwards shew (see Planting), in the trees of natural forests, no less than in the grasses and mosses which form a carpet upon the surface; and it is intimately connected with a similar arrangement which takes place in the soil, both with regard to quality, variation of surface, and moisture. It is equally observable in the animal creation, from the several varieties of man which inhabit different quarters of the globe, to the numerous species of insects or reptiles, which have each their particular habitats in plants or trees, or particular kinds of surfaces and local climates. It has hitherto been totally neglected, as most of nature's laws have been in this branch f science; while in its place is substituted, by custom and ignorance, a mode of arrangement totally inconsistent with nature or good taste" Loudon (1806, Vol. 1, p. 331f)The quotation marks seem to indicate that Loudon quoted someone else. However, I could not find any indication to a possible source in the vicinity of that passage.
The context of the passage quoted by Steuart and re-quoted by Matthew (1831) is a section on the effects of culture on trees:
"Book I, Sect. III: OF THE EFFECTS OF CULTURE ON TREES; IN REGARD TO CHARACTERISTIC BEAUTY AND TIMBER PRODUCE
It is remarkable, that this subject has never specifically engaged the attention of those who have written on planting. The effects of culture on other vegetables is so great, as always to change their appearance, and often in a considerable degree to alter their nature. The common culinary vegetables, and cultivated grasses, assume so different an appearance, in our fields and gardens, from what they do in a state of wild nature, that even a botanist might easily be deceived in regard to the species. The same general laws operate upon the whole kingdom of vegetables; and thence it is plain, that the effects of culture upon trees, though different in degree, must be analogous in their nature. It is true, that we are as yet possessed of no great number, either of experiments or observations, to enable us to determine, with minute accuracy, the precise extent of these effects; but still a person practically conversant with the subject, who shall pay attention to what he may observe taking place in different parts of the country, and who possesses a sufficient knowledge of the vegetable kingdom and physiology to reason from analogy, may deduce such general consequences as will suggest important practical rules." Loudon (1806, Vol. 2, p. 492)Well, that already sounds familiar to those who know Matthew's point about the effects of domestication on trees. Loudon then goes on to discuss the various effects of culture, including pruning, on the trees, not only with regard to timber quality, but also to aspects of beauty (garden and landscape design).
At page 516, his idea of a correlation between soils and plants is explicated once more for trees in forests:
"Now, as the properties of soils and situations are various, this naturally leads to a corresponding variation of the species of tree also; and this variation at once produces ornament and utility. Now, in natural forests, such an arrangement actually takes place. Thus in one part, we find the oak as the principal tree; [...] The arrangement goes on thus throughout the whole forest; and if the soil were examined, it would be found to vary correspondingly with the trees. Where the oak abounds, it will be found deep and good; dry where the beech prospers, and moist where the alder prevails." Loudon (1806, Vol. 2, p. 516)Later, however, Loudon (1806, Vol. 2, p. 561) cautions against overdoing pruning and recommends thinning as preferable. He compares thinning to a natural process of selection:
"Natural woods, sown by birds or the winds upon different kinds of surface and various sorts of soil, spring up at different times, and of different degrees of thickness and vigour. Hence it is easy to conceive, that those in favourable circumstances will soon overtop the rest; and, if they do not kill, will at least weaken them so much as not to be affected by them, until at last the strongest trees find sufficient room. Thus, though nature be slow in her operations, yet she accomplishes her purpose in the most complete manner. Artificial thinning is only assisting nature [...]" Loudon (1806, Vol. 2, p. 564)Compare this with the passage ending Matthew's criticism of Loudon:
"The use of the infinite seedling varieties in the families of plants, even in those in a state of nature, differing in luxuriance of growth and local adaptation, seems to be to give one individual (the strongest best circumstance-suited) superiority over others of its kind around, that it may, by overtopping and smothering them, procure room for full extension, and thus afford, at the same time, a continual selection of the strongest, best circumstance-suited, for reproduction. Man's interference, by preventing this natural process of selection among plants, independent of the wider range of circumstances to which he introduces them, has increased the difference in varieties, particularly in the more domesticated kinds; and even in man himself, the greater uniformity, and more general vigour among savage tribes, is referrible to nearly similar selecting law—the weaker individual sinking under the ill treatment of the stronger, or under the common hardship." Matthew (1831, p. 307f)That means: Matthew picked a short passage, namely pages 502-505 from Loudon (1806, Vol. 2), out of its context and criticised it for what it said about pruning. That is already biased, because Loudon had not only the quality of timber in mind, but also the esthetic appearance of a tree. Loudon could recommend pruning for changing the overall habitus of a tree, where Matthew could not.
But to end his criticism of that re-quoted passage of Loudon with a formulation similar to what he could have found a mere 50 pages further downstream in the very same book so criticised would, according to current (and therefore Whiggish) standards, be judged grossly negligent if not dishonest. All that was still lacking from Loudon (1806) was the idea that natural selection could transform species.
Did Matthew not know the rest of Loudon's book? If so, why did Matthew not transport all the changes that Steuart introduced into the quote of Loudon, which Matthew pretended to only re-quote?
2. Loudon's Encyclopaedia of Gardening (1822)Anyway, Matthew surely knew the Encyclopaedia* of Gardening, for he chose to call Loudon "the Author" of that work. Therefore, I searched the Encyclopaedia of Gardening for passages relevant to the idea of natural selection and the transformation of species.
The following passages show that everything in Matthew (1831), that is relevant to the idea of evolution through natural selection, has already been present in Loudon's Encyclopaedia of Gardening. Here is Loudon's take on natural selection including, even, a notion of the transformation of species at the end (highlights mine):
" 465. From the various sources of vegetable reproduction, but particularly from the fertility and dispersion of the seed, the earth would soon be over-run with plants of the most prolific species, and converted again into a desert, if it were not that nature has set bounds to their propagation by subjecting them to the control of man, and to the depredations of the great mass of animals; as well as in confining the germination of their seeds to certain and peculiar habitations arising from soil, climate, altitude, and other circumstances. In order to form an idea of the manner in which these act upon vegetation; imagine that every year an enormous quantity of seeds, produced by the existing vegetables, are spread over the surface of the globe, by the winds and other causes already mentioned, all of these seeds which fall in places suitable for their vegetation, and are not destroyed by animals, germinate and produce plants; then among these plants, the strongest, and largest, and those to which the soil is best suited, developed themselves in number and magnitude so as to choke the others. Such is the general progress of nature, and among plants, as among animals, the strong flourish at the expense of the weak. These causes have operated for such a length of time, that the greater number of species are now fixed and considered as belonging to certain soils, situations, and climates, beyond which they seldom propagate themselves otherwise than by the hands of man." Loudon (1822. "An Encyclopaedia of Gardening, Part II, Book I, Sect. X.) London: Longman, Hurst, Rees, Brown and Green, p. 230)In the second edition from 1824, an additional sentence is added before the first sentence of the above quote: "Though plants are controlled by animals, yet they also control one another." (The passage is § no. 843 at page 186f in this edition).
Concerning the effect of culture on plants, Loudon states:
"The general effect of culture on plants is that of enlarging all their parts; but it often also alters their qualities, forms, and colours: it never, however, alters their primitive structure. [As an example of the latter he mentions that the flowers of potatoes are the same in the Andes and Siberia.] The culinary vegetables of our garden, compared with the same species species in their wild state, afford striking proofs of the influence of culture on both the magnitude and qualities of plants. [Examples from Brassica and others.]
The influence of culture on fruits is no less remarkable. The peach, in its wild state in Media, is poisonous, but cultivated in the plains of Isphahan and Egypt, it becomes one of the most delicious fruits. The effect of culture on the apple, pear, cherry, plum, and other fruits, is nearly as remarkable; for not only the fruit and leaves, but the general habits of the tree is altered in these and other species. [Refers to a book by Sickler which Humboldt praised.]
The influence of culture on plants of ornament is great in most species. The parts of all plants are enlarged, some are numerically increased, as in the case of double flowers; and what is most remarkable, even the colours are frequently changed, both in leaf, flower, and fruit." Loudon (1822, p. 248)The idea that culture can change everything except primitive structures of plants suggests that Loudon excluded the transformation of species from the range of what humans could effect. In the second edition (Loudon 1824) this passage is spread over §§ 949-953 (pp. 202-203). In both cases, Loudon then discusses the effects of culture on spreading species beyond their natural range.
Here is Loudon's take on how to form new varieties of species including, even, the analogy between artificial selection by humans and the unguided process of selection taking place, as it were, in nature:
" 545. To form new Varieties of Vegetables, it is necessary to take advantage of their sexual differences, and to operate (as already observed) in a manner analogous to crossing the breed in animals. Hence the origin of what is called obtaining new sorts of fruits, as well as by an inverse practice of preserving distinct sorts of annual or biennial plants already obtained. Even this practice is but an imitation of what takes place in nature by the agency of bees and other insects, and the wind; all the difference is, that man operates with a particular end in view, and selects individuals possessing the particular properties which he wishes to perpetuate or improve." Loudon (1822. An Encyclopaedia of Gardening. London: Longman et al., p. 263)This paragraph is slightly altered and enlarged in the second edition:
" 1013. To form new varieties of vegetables, as well as of flowers and useful plants of every description, it is necessary to take advantage of their sexual differences, and to operate in a manner analogous to crossing the breed in animals. Hence the origin of new sorts of fruits. Even this practice is but an imitation of what takes place in nature by the agency of bees and other insects, and the wind; all the difference is, that man operates with a particular end in view, and selects individuals possessing the particular properties which he wishes to perpetuate or improve. New varieties, or rather subvarieties, are formed by altering the habits of plants; dwarfing through want of nourishment; variegating by arenarious soils; giving or rather continuing peculiar habits when formed by nature, as in propagating from monstrosities—fasciculi of shoots, weeping shoots, shoots with peculiar leaves, flowers, fruits, etc." Loudon (1824. An Encyclopaedia of Gardening. London: Longman et al., p. 216)The same can also be found as § 1791 in a later edition (1835, p. 463).
Book I of Part II, The Science of Gardening, ends with a passage that has no paragraph number:
" The whole of gardening, as an art of culture, is but a varied development of the above fundamental practices, all founded in nature, and for the most part rationally and satisfactorily explained on chemical and physiological principles." Loudon (1822. An Encyclopaedia of Gardening. London: Longman et al., p. 263)This can also be found as § 1016 in the second edition (1824, p. 216) or as §1794 (1835, p. 463).
Much later,** the survival of the best adapted recurs again in Book III, which is on Arboriculture:
" Sir W. Chambers and U. Price agree in recommending the imitation of natural forests in the arrangement of the species. In these nature disseminates her plants by scattering their seeds, and the offspring rise round the parent in masses or breadths, depending on a variety of circumstances, but chiefly on the facility which these seeds afford for being carried to a distance by the wind, the rain, and by birds or other animals. So disseminated they spring up, different sorts together, affected by various circumstances of soil and situation; and arrive at maturity, contending with other plants and trees, and with the browsing of animals. At last, that species which had enjoyed a maximum of natural advantages is found to prevail as far as this maximum extended, stretching along in masses and angular portions of surface, till circumstances changing in favor of some other species, that takes the prevalence in its turn. In this way it will generally be found, that the number of species, and the extent and style of the masses in which they prevail, bears a strict analogy to the changes of soil and surface; and this holds good, not only with respect to trees and shrubs, but to plants, grasses, and even the mossy tribe." Loudon (1822. An Encyclopaedia of Gardening. London: Longman et al., p. 1100f)This is § 6871 in the second edition (Loudon 1824, p. 957).
Throughout the work, Loudon advices his readers to propagate plants by selecting offspring from the strongest specimens. On propagating Asparagus, for example:
"It is best, however, to raise the plant from seed; and it is of considerable importance to gather it from the strongest and most compact shoots; such seed, as might naturally be expected, yielding by far the best plants." (Loudon 1822, p. 725)
ConclusionWe clearly have to count Loudon as yet another anticipator of the idea of natural selection. In particular, Loudon (1806, Vol. 2, p. 564) and Loudon (1822, 230) wrapped it up:
"Hence it is easy to conceive, that those in favourable circumstances will soon overtop the rest; and, if they do not kill, will at least weaken them so much as not to be affected by them, until at last the strongest trees find sufficient room."
" imagine that every year an enormous quantity of seeds, produced by the existing vegetables, are spread over the surface of the globe, by the winds and other causes already mentioned, all of these seeds which fall in places suitable for their vegetation, and are not destroyed by animals, germinate and produce plants; then among these plants, the strongest, and largest, and those to which the soil is best suited, developed themselves in number and magnitude so as to choke the others. Such is the general progress of nature, and among plants, as among animals, the strong flourish at the expense of the weak. These causes have operated for such a length of time, that the greater number of species are now fixed and considered as belonging to certain soils, situations, and climates, beyond which they seldom propagate themselves otherwise than by the hands of man."He was mute about the idea that this selection might also transform species, but his statement about a Deity (Loudon (1806, Vol. 1, p. 192) suggests that he did not fathom that possibility.
Loudon's anonymous review of Matthew (1831) also gets another significance, now that we know he had formulated the idea of natural selection. In it Loudon wrote: "One of the subjects discussed in this [Matthew's] appendix is the puzzling one, of the origin of species and varieties; and if the author has hereon originated no original views (and of this we are far from certain), he has certainly exhibited his own in an original manner." (Anonymous, attributed to Loudon, 1832. “Matthew, Patrick: On Naval Timber and Arboriculture.” Gardener's Magazine and Register of Rural & Domestic Improvements, vol. 8: pp.702-3).
Matthew, like Darwin and Wallace, has simply put the existing pieces of the puzzle together, but discovered no new piece himself. As was the standard of citation back then, as long as the solution to the puzzle was new, nobody felt the need to scrupulously cite the sources for the pieces.
Loudon may even have been the common source of Matthew and Darwin. For example, Darwin's notebooks titled 'Books to be read' and 'Books Read' (1838-1851) record for the 18 August 1842: "Skimmed through Encyclopaedia of Gardening ref: at end — [Loudon 1822]" (Darwin Online, http://darwin-online.org.uk/).
---Notes---*The word encyclopaedia in the title should not be misconstrued. Modern encyclopedias derived from dictionaries with the difference that they list factual knowledge alphabetically instead of grammatical and etymological knowledge. Loudon's book on gardening is not alphabetically ordered. His calling it an encyclopedia is probably only reflects his hope to produce a comprehensive handbook for gardeners. We'd today rather call it a textbook.
** Part I of the Encyclopaedia of Gardening extends from page 3 to page 118 and is headed History of Gardening. Book I categorizes this history according to nations from antiquity to the present of Loudon, whereas book II deals with the effects of political systems on gardening.
Most quotes relevant to natural selection are from Part II of the Encyclopaedia, which is headed Science of Gardening and extends from page 118 on. Book I (pp. 118-216) of that part deals with the science of the plants themselves, whereas Book II (pp. 217-267) deals with Natural Agents of Vegetable Growth. It's about what we'd today call environmental factors such as soil, climate, manure etc. Book II of Part II seems to contain no passages relevant to natural selection, but it may be the source for other ideas of Matthew, for example, on vegetable mould. Book III (pp. 268-363) is about Mechanical Agents of Gardening (tools, instruments, machines including fixed structures, hot-houses, economical buildings, apiaries, aviaries etc). Book IV (pp. 363-454) is about Operations of Gardening.
Part III is on the Practice of Gardening (Book I: Horticulture: pp. 454-789). For some reason the third edition of "A Catalogue of the Fruits Cultivated in the Garden of the Horticultural Society of London" (1842, pp. 182) is inserted between pages 776 and 777 of the Encycolpaedia of Gardening (1824). Thereafter Book I of Part III commences. Book II is on Floriculture (pp. 789-934) and Book III on Arboriculture (pp. 935-994). The last quote given above that bears on natural selection is from this part. Book IV (Landscape Gardening: pp.994-1039). Part IV with statistics commences.