260 LAMARCK, HIS LIFE AND WORK 
appeal to pronounce on this great subject when you 
have sufficiently examined and followed all the facts 
which relate to it. 
“Tf among living bodies there are any the con- 
sideration of whose organization and of the phe- 
nomena which they produce can enlighten us as to 
the power of nature and its course relatively to the 
existence of these bodies, also as to the variations 
which they undergo, we certainly have to seek for 
them in the lowest classes of the two organic king- 
doms (the animals and the plants). It is in the classes 
which comprise the living bodies whose organization 
is the least complex that we can observe and bring to- 
gether facts the most luminous, observations the most 
decisive on the origin of these bodies, on their repro- 
duction and their admirable diversification, finally on 
the formation and the development of their different 
organs, the whole process being aided by the concur- 
rence of generations, of time, and of circumstances. 
“Tt is, indeed, among living bodies the most multi- 
plied, the most numerous in nature, the most prompt 
and easy to regenerate themselves, that we should 
seek the most instructive facts bearing on the course 
of nature and on the means she has employed to 
create her innumerable productions. In this case we 
perceive that, relatively to the animal kingdom, we 
should chiefly give our attention to the invertebrate 
animals, because their enormous multiplicity in nature, 
the singular diversity of their systems of organization 
and of their means of multiplication, their increasing 
simplification, and the extreme fugacity of those which 
compose the lowest orders of these animals, show us 
much better than the others the true course of nature, 
and the means which she has used and which she is 
still incessantly employing to give existence to all the 
living bodies of which we have knowledge. 
‘“‘Hfer course and her means are without doubt the 
same for the production of the different plants which 
