Delage 265 
each change which their particular substance experiences 
in the egg. 
In the third place, this would at all events suffice 
only for the explanation of inheritance of those char- 
acters which develop in the parent organism under the 
influence of definite chemical actions, distributed through- 
out the whole body, and acting only upon those particles 
or cells of the body which have a certain chemical com- 
position. But what explanation could that give of true 
morphological inheritance and so of the inheritability 
of the growth or of the atrophy of an organ resulting 
from too much or too little use?—of the inheritability 
of the spongy structure of bone, of the conformation of 
the eye, and of all functional adaptations in general? 
Yet Delage gives the following explanation of the 
inheritance of the atrophy of unused organs. 
“That only is determined in the egg, which is not 
determined by functional excitation, but the amount 
determined by the latter is enormous.” The absolute 
uselessness of slight reductions of the atrophied femur 
of the whale and the consequent inefficacy, in this respect, 
of natural selection, and on the other hand, the impos- 
sibility of understanding how the slight reduction in 
volume which the femur undergoes during the life of 
the individual can extend its influence to the egg, and 
determine in that the modification necessary for the 
reproduction, in the following generations, of this new 
reduction in volume, ‘forces us to admit,” continues the 
author, “that neither in consequence of a fortuitous 
variation fixed by natural selection, nor in consequence 
of an acquired and inherited modification does the egg 
of the existing whale differ in so far as the femur is 
concerned, from the eggs which produced the whales 
