254 LAMARCK, HIS LIFE AND WORK 
details and immense nomenclature of the prodigious 
quantity of animals among which we distinguish an 
illimitable number of species, “but what is more 
worthy of you, and of more educational value, you 
should seek to know the course of nature.” ‘ You 
may enter upon the study of classes, orders, genera, 
and even of the most interesting species, because this 
would be useful to you; but you should never forget 
that all these subdivisions, which could not, however, 
be well spared, are artificial, and that nature does not 
recognize any of them.” 
“Tn the opening lecture of my last year’s course I 
tried to convince you that it is only in the organiza- 
tion of animals that we find the foundation of the 
natural relations between the different groups, where 
they diverge and where they approach each other. 
Finally, I tried to show you that the enormous series 
of animals which nature has produced presents, from 
that of its extremities where are placed the most per- 
fect animals, down to that which comprises the most 
imperfect, or the most simple, an evident modifica- 
tion, though irregularly defined (zuancé), in the struc- 
ture of the organization. 
“To-day, after having recalled some of the essen- 
tial considerations which form the base of this great 
truth; after having shown you the principal means 
by which nature is enabled to create (oférer) her in- 
numerable productions and to vary them infinitely ; 
finally, after having made you see that in the use she 
has made of her power of generating and multiplying 
living beings she has necessarily proceeded from the 
more simple to the more complex, gradually comph- 
cating the organization of these bodies, as also the 
composition of their substance, while also in that 
which she has done on non-living bodies she has oc- 
