PROFESSOR OF INVERTEBRATE ZOOLOGY 39 
engaged in foreign wars, the philosophers preserved in 
some degree, at least, the traditional calm of their pro- 
fession, and passed their days and nights in absorption 
in matters biological and physical. In 1801 appeared 
his Systeme des Antmaux sans Vertibres, preceded by 
the opening discourse of his lectures on the lower 
animals, in which his views on the origin of species 
were first propounded. During the years 1793-1798, 
or for a period of six years, he published nothing 
on zodlogy, and during this time only one paper 
appeared, in 1798, on the influence of the moon on 
the earth’s atmosphere. But as his memoirs on fire 
and on sound were published in 1798, it is evident 
that his leisure hours during this period, when not 
engaged in museum work and the preparation of his 
lectures, were devoted to meditations on physical and 
meteorological subjects, and most probably it was 
towards the end of this period that he brooded over 
and conceived his views on organic evolution. 
It appears that he was led, in the first place, to 
conchological studies through his warm friendship 
for a fellow naturalist, and this is one of many 
proofs of his affectionate, generous nature. The 
touching story is told by Etienne Geoffroy St. 
Hilaire.* 
“Tt was impossible to assign him a professorship of 
botany. M. de Lamarck, then forty-nine years old, 
accepted this change in his scientific studies to take 
charge of that which everybody had neglected; be- 
cause it was, indeed, a heavy load, this branch of 
natural history, where, with so varied relations, every- 
* Fragments Biographiques, p. 213. 
