t as the
various parts are from each other, and the effects of their use or
disuse are equally varied and complicated.

USE-INHERITANCE IMPLIES PANGENESIS.

How could the transmission of these varied effects to offspring be
accounted for? Is it possible to believe, with Mr. Spencer, that the
effects of use and disuse on the parts of the personal structure are
simultaneously registered in corresponding impressions on the seminal
germs? Must we not feel, with Darwin apparently,[70] that the _only_
intelligible explanation of use-inheritance is the hypothesis of
Pangenesis, according to which each modified cell, or physiological
unit, throws off similarly-modified gemmules or parts of itself, which
ultimately reproduce the change in offspring? If we reject pangenesis,
it becomes difficult to see how use-inheritance can be possible.

PANGENESIS IMPROBABLE.

The more important and best-known phenomena of heredity do not require
any such hypothesis, and leading facts (such as atavism, transmission of
lost parts, and the general non-transmission of acquired characters) are
so adverse to it that Darwin has to concede that many of the
reproductive gemmules are atavistic, and that by continuous
self-multiplication they may preserve a practical "continuity of
germ-substance," as Weismann would term it. The idea that the
relationship of offspring to parent is one of direct descent is, as
Galton tells us, "wholly untenable"; and the only reason he admits some
supplementary traces of pangenesis into his "Theory of Heredity,"[71] is
that he may thus account for the more or less questionable cases of the
transmission of acquired characters. But there appears to be no
necessity even for this concession. We ought therefore to dispense with
the useless and gratuitous hypothesis that cells multiply by throwing
off minute self-multiplying gemmules, as well as by the well-known
method of self-division. If pangenesis occurs, the transmission of
acquired characters ought to be a prominent fact. The size, strength,
health and other good or evil qualities of the cells could hardly fail
to exercise a marked and corresponding effect upon the size and quality
of the reproductive gemmules thrown off by those cells. The direct
evidence tends to show that these free gemmules do not exist.
Transfusion of blood has failed to affect inheritance in the slightest
degree. Pangenesis, with its attraction of gemmules from all parts of
the body into t