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asserts that when the germinal matter (of the residuum
of the stirp) is everywhere affected by the same conditions,
it would be everywhere affected in the same way ; that,
where the sexual elements are thus modified, they pro
duce corresponding modifications in the offspring ; and
last, but not least in importance, that the modification
in the parents’ organisms and sexual elements takes place
at the same time ; and sometimes the sexual elements
are modified when the body is not. Here, then, we have
a modification taking place before birth in all the indi
viduals subjected to a given influence—and a modification
which can be inherited by offspring. Whether the modi
fications of the body can be inherited or not, is a small
matter, if the sexual elements are similarly modified and
reproduce these modifications in offspring. These similar
variations will be reproduced and fixed in the race without
the intervention of the principle of selection.
Very similar to the theory of Mr. Galton is Dr. Weis-
mann's doctrine of the “ Continuity of the Germ Plasm,”
at which the author has laboured now for many years,
during which the theory has undergone considerable
modification. The germ plasm is the name given to the
contents of the germ cells, in sexual reproduction, the
germ cells are supposed to produce the cells which go
to build up the body of the offspring, and therefore called
somatic (body) cells. In doing this, it is possible that
all the contents of the germ cells should be used up in
producing the body cells, and that then the body cells
should produce the germ cells de novo. Or it is possible
that only a portion of the contents of the germ cells
should be used up, and that what remains should form
the germ cells of future generations. The first of these
conceivable methods Dr. Weismann designates as the
cyclical development of the germ plasm ; the latter he