t even a rudiment is left, suddenly reappears, as with the
fifth stamen in some Scrophulariaceae. We have already seen that reversion
acts in bud-reproduction; and we know that it occasionally acts during the
growth of the same individual animal, especially, but not exclusively, when
of crossed parentage,--as in the rare cases described of individual fowls,
pigeons, cattle, and rabbits, which have reverted as they advanced in years
to the colours of one of their parents or ancestors.

We are led to believe, as formerly explained, that every character which
occasionally reappears is present in a latent form in each generation, in
nearly the same manner as in male and female animals secondary characters
of the opposite sex lie latent, ready to be evolved when the reproductive
organs are injured. This comparison of the secondary sexual characters
which are latent in both sexes, with other latent characters, is the more
appropriate from the case recorded of the Hen, which assumed some of the
masculine characters, not of her own race, but of an early progenitor; she
thus exhibited at the same time the redevelopment of latent characters of
both kinds and connected both classes. In every living creature we may feel
assured that a host of lost characters lie ready to be evolved under proper
conditions. How can we make intelligible, and connect with other facts,
this wonderful and common capacity of reversion,--this power of calling
back to life long-lost characters? {374}

PART II.

I have now enumerated the chief facts which every one would desire to
connect by some intelligible bond. This can be done, as it seems to me, if
we make the following assumptions; if the first and chief one be not
rejected, the others, from being supported by various physiological
considerations, will not appear very improbable. It is almost universally
admitted that cells, or the units of the body, propagate themselves by
self-division or proliferation, retaining the same nature, and ultimately
becoming converted into the various tissues and substances of the body. But
besides this means of increase I assume that cells, before their conversion
into completely passive or "formed material," throw off minute granules or
atoms, which circulate freely throughout the system, and when supplied with
proper nutriment multiply by self-division, subsequently becoming developed
into cells like those from which they were derived. These granules for the
sake of