260 Evolution and Adaptation 
of disuse are inherited. There is, however, no proof that 
this is the case, although there are a number of instances to 
which this mode of explanation appears to give the readiest 
solution. But, as has been said before, it is not this kind 
of evidence that the theory is in need of, since Lamarck him- 
self gave an ample supply of illustrations. What we need is 
clear evidence that this sort of inheritance is possible, and, 
from the very nature of the case, it is just this evidence that 
fossil remains can never supply. 
The same criticism may be made of the work of Ryder, 
Packard, Dall, Jackson, Eimer, Cunningham, Semper, De 
‘ Varigny, and others of the Lamarckian school. Despite the 
' large number of cases that they have collected, which appear 
to them to be most easily explained on the assumption of 
the inheritance of acquired characters, the proof that such 
inheritance is possible is not forthcoming. Why not then 
spend a small part of the energy, that has been used to 
expound the theory, in demonstrating that such a thing is 
really possible? One of the chief virtues of the Lamarckian 
_ theory is that it is capable of experimental verification or con- 
tradiction, and who can be expected to furnish such proof if 
not the Neo-Lamarckians ? 
We may fairly sum up our position in regard to the theory 
of the inheritance of acquired characters in the verdict of 
“not proven.” Iam not sure that we should not be justified 
at present in claiming that the theory is unnecessary and 
even improbable. 
