1895.) Organie Variation. 889 
due to subsequent influences of the environment. In the case 
of two parents, the offspring might be expected to possess 
characteristics of each, now being strictly intermediate, now 
approaching one parent more nearly than the other. In this 
method of variation, which is nearly all that Weissmann ad- 
mits, the steady tendency must be to swamp all distinctions, 
the differences between parents continually diminishing. In 
short, these differences could never have arisen were heredity 
the only force at work. Darwinism has a similar tendency, 
since varying and ill-adapted organisms tend to disappear, 
and only those with close similarities of adaptation to be pre- 
served. The changes due to Lamarckian influences must tend 
also in the direction of uniformity, through a general move- 
ment of adaptation to fixed conditions. 
Yet this fixed tendency towards uniformitarianism is not 
what nature displays. Marked individual variations con- 
stantly appear, the seeming efforts of nature to produce similar 
forms being checked at every point by individual peculi- 
arities of constitution. These variations are in opposition to 
the influences of heredity, natural and sexual selection, use and 
effort, all of which tend to uniformity. To what are they due? 
Can a parent transmit to its offspring characteristics which it 
does not possess itself? This does not seem possible; the 
natural conclusion being that the offspring should repeat the 
peculiarities of the parent or parents existing at the period of 
its birth. 
Yet has heredity as overmastering an influence as many 
ascribe to it? Even if we decline to accept the Weissmann 
hypothesis, and hold that every portion of the organism, in 
some way, exerts a direct influence upon the developing germ, 
it is not impossible that this influence may differ in energy in 
different organisms, in some cases controlling almost abso- 
lutely the constitution of the germ, in others permitting foreign 
influences, external or internal, to operate to some extent, with 
consequent variations in germinal constitution. 
Several hypotheses have been advanced in explanation of 
heredity, none of them based sufficiently on discovered facts 
to be quite satisfactory, and all of them leaving it possible 
