is
wonderfully preserved, &c." In the _Origin_ this _preservation_ is
rather taken for granted.

{471} <In the margin is written> Aborted organs show, perhaps,
something about period <at> which changes supervene in embryo.

In several of the cases just enumerated we know that the first cause of
the peculiarity, when _not_ inherited, lies in the conditions to which
the animal is exposed during mature life, thus to a certain extent
general size and fatness, lameness in horses and in a lesser degree
blindness, gout and some other diseases are certainly in some degree
caused and accelerated by the habits of life, and these peculiarities
when transmitted to the offspring of the affected person reappear at a
nearly corresponding time of life. In medical works it is asserted
generally that at whatever period an hereditary disease appears in the
parent, it tends to reappear in the offspring at the same period. Again,
we find that early maturity, the season of reproduction and longevity
are transmitted to corresponding periods of life. Dr Holland has
insisted much on children of the same family exhibiting certain diseases
in similar and peculiar manners; my father has known three brothers{472}
die in very old age in a _singular_ comatose state; now to make these
latter cases strictly bear, the children of such families ought
similarly to suffer at corresponding times of life; this is probably not
the case, but such facts show that a tendency in a disease to appear at
particular stages of life can be transmitted through the germinal
vesicle to different individuals of the same family. It is then
certainly possible that diseases affecting widely different periods of
life can be transmitted. So little attention is paid to very young
domestic animals that I do not know whether any case is on record of
selected peculiarities in young animals, for instance, in the first
plumage of birds, being transmitted to their young. If, however, we turn
to silk-worms{473}, we find that the caterpillars and coccoons (which
must correspond to a _very early_ period of the embryonic life of
mammalia) vary, and that these varieties reappear in the offspring
caterpillars and coccoons.

{472} See p. 42, note 5.{Note 160}

{473} The evidence is given in _Var. under Dom._, I. p. 316.

I think these facts are sufficient to render it probable that at
whatever period of life any peculiarity (capable of being inherited)
app