230 LAMARCK, HIS LIFE AND WORK 
bearing on the stability of species, and though his 
work is largely a repetition of the Recherches, the 
author omits the passages quoted above. Was this 
period of six years, between 1794 and 1800, given to 
a reconsideration of the subject resulting in favor of 
the doctrine of descent ? 
Huxley quotes these passages, and then in a foot- 
note (p. 211), after stating that Lamarck’s Recherches 
was not published before 1794, and stating that at 
that time it presumably expressed Lamarck’s mature 
views, adds: “It would be interesting to know what 
brought about the change of opinion manifested in 
the Recherches sur l Organisation des Corps vivans, 
published only seven years later.” 
In the appendix to this book (1802) he thus refers 
to his change of views: “I have for a long time 
thought that speczes were constant in nature, and that 
they were constituted by the individuals which belong 
to each of them. Iam now convinced that I was in 
error in this respect, and that in reality only in- 
dividuals exist in nature” (p. 141). 
Some clew in answer to the question as to when 
Lamarck changed his views is afforded by an almost 
casual statement by Lamarck in the addition entitled 
Sur les Fossiles to his Systeme des Anitmaux sans 
Vertcbres (1801), where, after speaking of fossils as 
extremely valuable monuments for the study of the 
revolutions the earth has passed through at different 
regions on its surface, and of the changes living 
beings have there themselves successively undergone, 
he adds in parenthesis: “Dans mes lecons 7’ at toujours 
insiste sur ces considérations.” Are we to infer from 
