352 LAMARCK, HIS LIFE AND WORK 
We submit that this mode of evolution of the giraffe 
is quite as reasonable as the very hypothetical one 
advanced by Mr. Wallace;* z.¢., that a variety oc- 
curred with a longer neck than usual, and these “at 
once secured a fresh range of pasture over the same 
ground as their shorter-necked companions, and on 
the first scarcity of food were thereby enabled to out- 
live them.” Mr. Wallace’s account also of Lamarck’s 
general theory appears to us to be one-sided, inade- 
quate, and misleading. He states it thus: “The 
hypothesis of Lamarck—that progressive changes in 
species have been produced by the attempts of animals 
to increase the development of their own organs, 
and thus modify their structure and habits.” This is 
a caricature of what Lamarck really taught. Wants, 
needs (desozvs), volitions, desires, are not mentioned 
by Lamarck in his two fundamental laws (see p. 303), 
and when the word desozus is introduced it refers as 
much to the physiological needs as to the emo- 
tions of the animal resulting from some new environ- 
ment which forces it to adopt new habits such as 
means of locomotion or of acquiring food. 
It will be evident to one who has read the original 
or the foregoing translations of Lamarck’s writings 
that he does not refer so much to mental desires or 
volitions as to those physiological wants or needs 
thrust upon the animal by change of circumstances 
or by competition ; and his desozvs may include lust, 
hunger, as well as the necessity of making muscular 
exertions such as walking, running, leaping, climbing, 
swimming, or flying. 
* Natural Selection, pp. 41-42. 
