76 
(p. 121). And the closing sentence of this 
chapter : “‘ Whatever the cause may be of 
each slight difference in the offspring from 
their parents, and a cause for each must 
exist, it is the steady accumulation, through 
natural selection, of such differences, when 
beneficial to the individual, that gives rise 
to all the more important modifications of 
structure by which the innumerable beings 
on the face of this earth are enabled to 
struggle with each other, and the best 
adapted to survive ” (p. 153). 
I quote thus freely from this standard 
author and classic treatise on evolution, in 
order that we may see what the assump- 
tion in the case actually is, and also to show 
that it is a fundamental assumption at the 
very foundation of the current philosophy 
of evolution. The quotations are sufficient 
to show that it was assumed that particular 
variations are particularly caused, 7. e., while 
variability may be regarded as the possi- 
bility of varying, or the latent capability 
to vary, each variety was, by Darwin, con- 
sidered to be caused by a special something 
with which the organism comes into rela- 
tion and which did not operate upon its an- 
cestors. 
I do not propose here to discuss the 
metaphysical question as to whether an 
organism may or may not be said to pos- 
sess powers or potencies, properties or capa- 
bilities, or whether it is necessary or not to 
assume that an organism is capable of vary- 
ing before it does vary. But in this paper 
attention is called to the relation which a 
certain class of biological phenomena bear 
to another class of biological phenomena, 
and, so far as it may be possible to confine 
one’s attention to them, these phenomena 
alone will be considered. From this point 
of view variation is a deviation, in the 
order of sequence, of one series of phe- 
nomena from some other order of sequence 
with which it is compared. In the case of 
organisms the latter series of phenomena is 
SOCIENCE. 
[N.S. Von. VI. No. 133. 
that which the parent form (A) exhibits in 
the course of its growth from the ovum to 
maturity. The case we compare with it is 
the series of phenomena expressed by an 
offspring (B) in passing from the ovum to 
the mature stage. A variation occurs when- 
ever, in any particular stage of the series, 
B varies or deviates from the series A. 
Supposing such a deviation to take place 
the morphological character (v) expressed 
in the structure of the organism (B) is 
often and may properly be called a varia- 
tion. The whole organism B, with its 
added character (v), is often spoken of in 
biology as a variety of A, and all descend- 
ants of A exhibiting the variation (v) are 
said to be of this variety (Bv). As I un- 
derstand the Darwinian doctrine (and I 
believe this is the generally accepted doc- 
trine on this point) it is assumed that 
except for some special cause acting upon 
the organism A, or its ancestors for each 
particular variation (v) of this kind, there 
would appear no deviation in B, there 
would arise no variety By. Let us be care- 
ful not to raise the question whether the 
organism could vary or could not; the 
question is purely regarding the order of 
the phenomena. It is a question of science 
as to whether the variation takes place on 
account of some cause (I use the word 
used by Darwin and suppose we may infer 
that he means some interference with the 
course of phenomena taking place in the 
developing organism), and I raise the ques- 
tion : Have we any evidence to support the 
opinion that variations would not occur 
except for some such interference with the 
normal processes of development exhibited 
by the growing individual ? 
If we examine Professor Cope’s ‘ Primary 
Factors of Organic Evolution,’ standing, as 
it does, for the most extreme of the Neo-La- 
marckian school of naturalists as con- 
trasted with the Darwinian, we find a simi- 
lar assumption on this point. Cope divides 
