296 EVOLUTION IN BIOLOGY. [LECT. 



"686. Tous les individus de cette nature, qui existent, pro- 

 viennent d'individus semblables qui tous ensemble constituent 

 1'espece entiere. Or, je crois qu'il est aussi impossible a rhomme 

 de conn6itre la cause physique du premier individu de chaque 

 espece, que d'assigner aussi physiquement la cause de 1'existence 

 de la matiere ou de 1'univers entier. C'est au moins ce que le 

 re*sultat de mes connaissances et de mes reflexions me portent a 

 penser. S'il existe beaucoup de varie"te"s produites par 1'effet des 

 circonstances, ces varie"tes ne denaturent point les especes ; mais 

 on se trompe, sans doute souvent, en indiquant comme espece, ce 

 qui n'est que varie"t6 ; et alors je sens que cette erreur peut tirer 

 a consequence dans les raisonnements que Ton fait sur cette 

 matiere." 1 



The first three volumes of Treviranus's " Biologie," 

 which contain his general views of evolution, appeared 

 between 1802 and 1805. The " Eecherches sur 1'organ- 

 isation des corps vivants," in which the outlines of 

 Lamarck's doctrines are given, was published in 1802 ; 

 but the full development of his views, in the " Philo- 

 sophic Zoologique," did not take place until 1809. 



The "Biologie" and the" Philosophic Zoologique" are 

 both very remarkable productions, and are still worthy 

 of attentive study, but they fell upon evil times. 

 The vast authority of Cuvier was employed in support 

 of the traditionally respectable hypotheses of special 

 creation and of catastrophism ; and the wild specula- 

 tions of the "Discours sur les Kevolutions de la Surface 



1 " Recherches sur les causes des principaux faits physiques," par J. 

 B. Lamarck. Paris. Seconde annee de la Republique. In the preface, 

 Lamarck says that the work was written in 1776, and presented to the 

 Academy in 1780 ; but it was not published before 1794, and, at that 

 time, it presumably expressed Lamarck's mature views. It would be 

 interesting to know what brought about the change of opinion mani- 

 fested in the " Recherches sur 1'organisation des corps vivants," published 

 only seven years later. 



