1S90.] 
45 
[Jeffries. 
with Lamarck’s. It can also be shown by palaeontology and mor- 
phology how an organ has slowly increased and developed and 
logically can be attributed to use. 
Curiously enough the converse has been universally accepted, 
that disused organs abort. This can only occur if the atrophy 
produced by disuse is transmitted to the young as such it is ad- 
vanced by Lamarck and adopted by Darwin. In this case, as with 
most of Lamarck’s laws, Darwin has taken them to himself wher- 
ever natural selection, sexual selection and the like have fallen to 
the ground. 
Darwin’s natural selection does not depend, as is popularly sup- 
posed on direct proof, but is adduced as an hypothesis which gains 
its strength from being compatible with so many facts of correla- 
tion between an organism and its surroundings. Yet the same 
writer who considers natural selection proved will call for positive 
experimental proof of Lamarck’s theory and refuse to accept its 
general compatibility with the facts as support. Almost any 
case where natural selection is held to act by virtue of advantage 
gained by use of a part is equally compatible with Lamarck’s the- 
ory of use and development. The wings of birds of great power 
of flight, the relations of insects to flowers, the claws of beasts of 
prey are all cases in point. 
The essential difference between Lamarck and Darwin is that 
the latter has added on the factors of death and failure to propa- 
gate. Lamarck says outside conditions cause organisms to vary, 
hence new species. Darwin says the same with the addition that 
the less adapted forms are killed off. This is clearly so of mon- 
strous variations, but the majority of deaths are either from vio- 
lence, when coincidence as regards condition must play an over- 
whelming part over slight bodily differences, or from parasitism 
which barring a few peculiar breeds as white rats and highbred 
hogs pays no attention to variations in the species. 
Cases of adaption for passive concealment or passive protec- 
tion obviously cannot be explained by habit. If, however, the or- 
ganism must receive from the outside the force which first causes 
it to vary in such a way as to enjoy protection why is the advan- 
tage of protection called for to explain the new variety ? Favor- 
able or unfavorable, driven by Fate, the change must pursue its 
course. 
The belief in the power of physical causes to affect an organ- 
