1264 Recent Literature. [ December, 
transmit the same variation to its ovarian ova by direct inheri- 
tance, the characteristic will be established as an hereditary race- 
characteristic, and will be perpetuated and transmitted, by the 
selected individuals and their descendants, without gemmules. 
“ According to this view, the origin of a new variation is 
neither purely fortuitous nor due to the direct and definite modi- 
fying influence of changed conditions. A change in the environ- 
ment of a cell causes it to throw off gemmules, and thus to trans- 
mit to descendants a tendency to vary in the part which is affected 
by the change. 
“ The occurrence of a variation is due to the direct action of 
external conditions, but its precise character is not. My view of 
the cause of variation is thus seen to be midway between that 
accepted by Darwin and that advocated by Semper and other 
Lamarckians,” 
In a word then, Brooks’ theory maintains that these gemmules 
only by chance pervade the whole body, but are, as a rule, con- 
fined to the male cell or spermatozoon, hence the male element 
is the originating and the female the perpetuating factor; the 
ovum is conservative; the male cell progressive, Heredity of 
ued 
silver-gray rabbit, produced no effect. These gemmules are me ri 
test the theory properly we should think experiments might n ; 
is carefully thought out, well present 
bution of permanent value to a most 
of r 
always to detect the operation of the law 
peculation in good hands has always 
discovery, and the simple endeavor to discover t 
ity may at least lead to fresh fields of research. ~ 
After stating the theory, our author devotes a large P 
been a fruitful soure" 
he laws of here® 
