316 The American Naturalist. April, 
Hoffmann has given to the wild carrot a new character through 
long cultivation ; this character has become inherited,—that is to 
say, seeds of the plants showing this acquired character show it _ 
again if placed in the same conditions. But let us plant the 
seeds in the original place; they do not receive the food they 
had in the cultivated ground, and will in a very short time fall 
back to the original wild state; simply, as it seems, because the 
conditions under which the character appeared are not given any 
more. The word inheritance is very often used in an absolutely 
wrong and misleading way. We cannot speak of direct inherit- 
ance of an acquired character; what is called here inheritance is 
simply the reappearance of the acquired character under the same — i 
stimulus; it is not, strictly speaking, inherited. For instance, we 
cannot say that the reduction of the biting muscles of lap-dogs 
is directly inherited. The biting muscles are simply kept low by 
the effect of the peculiar soft food that these animals receive, and — 
by their peculiar mode of living ; but if we change the food and ' k 
bring the animal into different conditions, these muscles will 
increase again. 
Inheritanċe is somewhat comparable to reflex motion and 
automatic motion. Inheritance in its beginning is comparable to 
reflex motion,—that is to say, a certain character appears undera 
certain stimulus. Inheritance is comparable to automatic motion oA 
when a certain character appears without that stimulus. In other” - 
words, the germ is first reflective, then automatic. oe 
The difference between my opinion and that of Weismann is this: 
According to Weismann, the mingling of germ-plasma of different 
individuals produces variation, on which natural selection acis 2 
According to my opinion, variation is the product of the stimulus 
of the conditions on the germ and somatic plasm ; it is therefore 
definite. Variation goes on in certain definite lines. It is the 
surroundings which change the germ and somatic plasm, W! s ; 
determine variation. E 
That variation goes in definite lines, determined by the cond 
tions in which the organism lives, is admitted by all those W" 
ever studied species; I mean by all those who studied, for instanc®, 
all the representatives of a single genus and its g bye ses 
a ees 
