1892.] Heredity of Acquired Characters. 895 
as the sole factors for natural selection to act upon. In order 
to evolve two adult forms that are precisely alike in every 
detail, from two germs with the same identical qualities and 
tendencies, there must be in each case the same metabolic 
activity of every part of the system, giving rise to the same 
-series of anastates in the constructive processes of every organ, 
and the same series of katastates in destructive metabolism, 
throughout the entire period of growth, which would of course 
rarely occur from a lack of uniformity in the surrounding con- 
ditions of the two individuals. 
Individual variations, which are so frequently observed, are 
then readily accounted for, and there are no physiological 
reasons for the assumption that the metabolic bias of the 
organism which gives rise to them, does not likewise have an 
influence on the germ cells. 
The non-appearance of an acquired habit, or peculiarity of 
the organism in the next generation, cannot be accepted 
as evidence that it has not been potentially transmitted. 
The known facts of atavism show that an inherited pecul- 
iarity of the organism may be obscured for several gener- 
ations by other characters, and then reassert itself with all its 
original intensity. The established family characters, and the 
acquired habit or peculiarity, of the individual, represent 
antagonistic factors, and their relative intensity in connection 
with conditions of development must determine which is to 
dominate in the offspring. 
The transmission of a character, in the first place, should 
not be manifest in a direct reproduction of the morphological 
peculiarity, but it must consist in a habit of the organism 
that leads to the development of the peculiarity in the off- 
spring under favorable conditions for its exercise. The failure 
of the effects of injuries or mutilations to make their appear- 
ance in the offspring cannot be admitted as evidence to prove 
the non-inheritance of acquired characters, as the physiologi- 
cal activities of the system that are required to produce the 
morphological peculiarity have not been established, and there 
can be no tendency of the organism to reproduce them. 
