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selection. And, finally, if it be recollected that Mr. Darwin's and Mr. Wallace's essays were published simultaneously in the “Journal of the Linnaean Society" for 1858, it follows that the Reviewer, while obliquely depreciating Mr. Darwin's deserts, has in reality awarded to him a priority which, in legal strictness, does not exist.

Mr. Mivart, whose opinions so often concur with those of the Quarterly Reviewer, puts the case in a way, which I much regret to be obliged to say, is, in my judgment, quite as incorrect; though the injustice may be less glaring. He says that the theory of natural selection is, in general, exclusively associated with the name of Mr. Darwin, “on account of the noble self-abnegation of Mr. Wallace.” As I have said, no one can honour Mr. Wallace more than I do, both for what he has done and for what he has not done, in his relation to Mr. Darwin. And perhaps nothing is more creditable to him than his frank declaration that he could not have written such a work as the “Origin of Species.” But, by this declaration, the person most directly interested in the matter repudiates, by anticipation, Mr. Mivart's suggestion that Mr. Darwin's eminence is more or less due to Mr. Wallace's modesty.

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VI
EVOLUTION IN BIOLOGY
[1878].

IN the former half of the eighteenth century, the term “evolution” was introduced into biological writings, in order to denote the mode in which some of the most eminent physiologists of that time conceived that the generations of living things took place; in opposition to the hypothesis advocated, in the preceding century, by Harvey in that remarkable work which would give him a claim to rank among the founders of biological science, even had he not been the discoverer of the circulation of the blood. One of Harvey's prime objects is to defend and establish, on the basis of direct observation, the opinion already held by Aristotle; that, in the higher animals at any rate, the formation of the

* The Exercitationes de Generatione Animalium, which Dr George Ent extracted from him and published in 1651.

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I

188 EvOLUTION IN BIOLOGY vr

mew organism by the process of generation takes place, mot suddenly, by simultaneous accretion of rudiments of all, or of the most important, of the organs of the adult; norby suddem metamorphosis of a formative substance into a miniature of the whole, which subsequently grows; butby cpigenesis, or successive differentiation of a relatively homogeneous rudiment into the parts and structures which are characteristic of the adult.

** Et primò, quidem, quoniam per epigenesin sive partium superexorientium additamentum pullum fabricari certum est : quænam pars ante alias omnes exstruatur, et quid deilla ejusque generandi modo observandum veniat, dispiciemus. Ratum sane est et in ovo manifestè apparet quod Aristoteles de perfectorum animalium generatione enuntiat: nimirum, non omnes partes simul fieri, sed ordine aliam post aliam ; primùmque existere particulam genitalem, cujusvirtute postea (tanquam ex principio quodam) reliquæ omnes partes prosiliant. Qualem in plantarum seminibus (fabis, putà, aut glandibus) gemmam sive apicem protuberantem cernimus, totius futuræ arboris principium. Estque hæc particula velut filius emancipatus seorsumque collocatus, et principium per se vivens ; unde postea membrorum ordo describάtur; et quæcumque ad absolvendum animal pertinent, disponwntur.* Quoniam enim nulla pars se ipsam generat ; sed postquam generata est, se ipsam jam auget ; ideo eam primùm oriri mecesse est, quæ principium augendi contineat (sive enim planta, sive animal est, æque omnibus inest quod vim habeat vegetandi, sive nutriendi),* simulque reliquas omnes partes suo quamque ordine distinguat et formet; proindeque in eadem primogenita particula anima primarioinest, sensus, motusque, et totius vitæ auctor et principium.” (Exercitatio 51.)

* De Generatione Animalium, lib. ii. cap. x,
* De Generatione, lib. ii. cap. iv.

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Harvey proceeds to contrast this view with that of the “Medici,” or followers of Hippocrates and Galen, who, “badly philosophising,” imagined that the brain, the heart, and the liver were simultaneously first generated in the form of vesicles; and, at the same time, while expressing his agreement with Aristotle in the principle of epigenesis, he maintains that it is the blood which is the primal generative part, and not, as Aristotle thought, the heart.

In the latter part of the seventeenth century, the doctrine of epigenesis, thus advocated by Harvey, was controverted, on the ground of direct observation, by Malpighi, who affirmed that the body of the chick is to be seen in the egg, before the punctum sanguineum makes it appearance. But, from this perfectly correct observation a conclusion which is by no means warranted was drawn; namely, that the chick, as a whole, really exists in the egg antecedently to incubation; and that what happens in the course of the latter process is no addition of new parts, “alias post alias natas,” as Harvey puts it, but a simple expansion, or unfolding, of the organs which already exist, though they are too small and inconspicuous to be discovered. The weight of Malpighi's observations therefore fell into the scale of that doctrine which Harvey terms metamorphosis, in contradistinction to epigenesis.

The views of Malphigi were warmly welcomed,

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on philosophical grounds, by Leibnitz,* who found in them a support to his hypothesis of monads, and by Malebranche ;* while, in the middle ofthe eighteenth century, not only speculative considerations, but a great number of new and interesting observations on the phenomena of generation, led the ingenious Bonnet, and Haller,o the first physiologist of the age, to adopt, advocate, and extend them.

* " Cependant, pour revenir aux formes ordinaires ou aux âmes matérielles, cette durée qu'il leur faut attribuer à la place de celle qu'on avoit attribuée aux atomes pourroit faire douter si elles ne vont pas de corps en corps ; ce qui seroit la métempsychose, à peu près comme quelques philosophes ont cru la transmission du mouvement et celle des espèces. Mais cette imagination est bien éloignée de la nature des choses. Il n'y a point de tel passage ; et c'est ici où les transformations de Messieurs Swammerdam, Malpighi, et Leewenhoek, qui sont des plus excellens observateurs de notre tems, sont venues à mon secours, et m'ont fait admettre plus aisément, que l'animal, et toute autre substance organisée ne commence point lorsque nous le croyons, et que sa generation apparente n'est qu'une développement et une espèce d'augmentation. Aussi ai je remarqué que l'auteur de la Recherche de la Verité, M. Regis, M. Hartsoeker, et d'autres habiles hommes n'ont pas été fort éloignés de ce sentiment." Leibnitz, Système Nouveau de la Naiure, 1695. The doctrine of** Emboîtement " is contained in the Considérations sur le Principe de Vie, 1705 : the preface to the Theodicée, 1710 ; and the Principes de la Nature et de la grace (S 6), 1718.

* o Il est vrai que la pensée la plus raisonnable et la plus conforme à l'experience sur cette question très difficile de la formation du fœtus : c'est que les enfans sont déja presque tout formés avant même l'action par laquelle ils sont conçus , et que leurs mères ne font que leur donner l'accroissement ordinaire dans le temps de la grossesse." De la Recherche de la Verité, livre ii. chap. vii. p. 334, 7th ed., 1721.

* The writer is indebted to Dr. Allen Thomson for reference to the evidence contained in a note to Haller's edition of Boerhaave's Proelectiones Academicœ, vol v. pt. ii. p. 497, published in 1744, that Haller originally advocated epigenesis,

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