its ultimate limits and extreme consequences seems to
indicate that it is at once insufficient and cumbrous.

Mr. Darwin himself is, of course, fully aware that there must be _some_
limit to this aggregation of gemmules. He says:[220] "Excessively minute
and numerous as they are believed to be, an infinite number derived, during
a long course of modification and descent, from each cell of each
progenitor, could not be supported and nourished by the organism."

But apart from these matters, which will be more fully considered further
on, the hypothesis not only does not appear to account for certain
phenomena which, in order to be a valid theory, it ought to account for;
but it seems absolutely to conflict with patent and notorious facts.

How, for example, does it explain the peculiar reproduction which is {211}
found to take place in certain marine worms--certain annelids?

[Illustration: AN ANNELID DIVIDING SPONTANEOUSLY.
(A new head having been formed towards the hinder end of the body of the
parent.)]

In such creatures we see that, from time to time, one of the segments of
the body gradually becomes modified till it assumes the condition of a
head, and this remarkable phenomenon is repeated again and again, the body
of the worm thus multiplying serially into new individuals which
successively detach themselves from the older portion. The development of
such a mode of reproduction by "Natural Selection" seems not less
inexplicable than does its continued performance through the aid of {212}
"pangenesis." For how can gemmules attach themselves to others to which
they do not normally or generally succeed? Scarcely less difficult to
understand is the process of the stomach-carrying-off mode of metamorphosis
before spoken of as existing in the Echinoderms. Next, as to certain patent
and notorious facts: On the hypothesis of pangenesis, no creature can
develop an organ unless it possesses the component gemmules which serve for
its formation. No creature can possess such gemmules unless it inherits
them from its parents, grandparents, or its less remote ancestors. Now, the
Jews are remarkably scrupulous as to marriage, and rarely contract such a
union with individuals not of their own race. This practice has gone on for
thousands of years, and similarly also for thousands of years the rite of
circumcision has been unfailingly and carefully performed. If then the
hypothesis of pangenesis is well founded, that rite o