LAMARCK’S THEORY OF EVOLUTION 2 
into very different situations from those where the 
others occur, and then constantly submitted to other 
influences—the former, I say, assume new forms as 
the result of a long habit of this other mode of exist- 
ence, and then they constitute a new species, which 
comprehends all the individuals which occur in the 
same condition of existence. We see, then, the faith- 
ful picture of that which happened in this respect in 
nature, and of that which the observation of its acts 
can alone discover to us.” 
Ill. Lamarck’s Views on Species, as published in 1803. 
In the opening lecture* of his course at the Mu- 
seum of Natural History, delivered in prairial (May 
20-June 18), 1803, we have a further statement of 
the theoretical views of Lamarck on species and their 
origin. He addresses his audience as “ Citoyens,” 
France still being under the régzme of the Republic. 
The brochure containing this address is exceed- 
ingly rare, the only copy existing, as far as we know, 
being in the library of the Museum of Natural His- 
tory in Paris. The author’s name is not even given, 
and there is no imprint. Lamarck’s name, however, 
is written on the outside of the cover of the copy we 
have translated. At the end of the otherwise blank 
page succeeding the last page (p. 46) is printed the 
words: Esgutsse @un Philosophie soologique, the pre- 
liminary sketch, however, never having been added. 
He begins by telling his hearers that they should 
not desire to burden their memories with the infinite 
* Discours d ouverture d’un Cours de Zoologie, prononcé en prairial, 
an XI, au Muséum ad Histoire naturelle, sur la question, Qwest-ce 
que l’espece parmi les corps vivans ? (1803). 
