468
GENERATION.
dation, or the laws by which this change is
regulated, it be in any respect analogous in its
nature to the operation of certain poisonous or
contagious principles, as for example, the
venereal virus, vaccine matter, the contagious
principle of small-pox, measles, scarlatina,
plague, fevers, &c. The inimitable Harvey
thus expresses himself regarding the essential
nature of fecundation in different parts of the
forty-ninth Exercitation on the efficient cause
of the chicken. “ Although it be a known
thing subscribed by all that the fœtus assumes
its original and birth from the male and female,
and consequently that the egge is produced
by the cock and henne, and the chicken out of
the egge, yet neither the schools of Physicians
nor Aristotle’s discerning brain have disclosed
the manner how the cock and its seed doth
mint and coine the chicken out of the egge.”
“ This,” he says, “ is agreed upon by universal
consent; that all animals whatsoever, which
arise from male and female, are generated by
the coition of both sexes, and so begotten as it
were per contagium aliquod, by a kind of con¬
tagion.” “ Even also,” he says, “ by a breath
or miasma,” referring to the fecundation of the
ova of fishes out of the body.
“ The lac maris, male’s milk, propagating or
genital liquor, vitale virus, vital or quickening
venom,” are all names of the seminal fluid of
the male. Again, “ The efficient in an egge,
by a plastica! vertue (because the male did
only touch, though he be now far from touching
and have no extremity reached out to it) doth
frame and set up a fœtus in its own species
and resemblance.” “ What is there in genera¬
tion, that by a momentary touch (nay not
touching at all, unlesse through the sides of
many mediums) can orderly constitute the parts
of the chicken by an epigenesis, and produce
an univocal creature and its own like ? and for
no other reason but because it touched here¬
tofore.”
« The qualities of both parents are observable
in the offspring, or the paternal and maternal
handy-work may be tracked and pointed out
both in the body and soul.” The first cause
must therefore be of a mixed kind. « It is
required of the primary efficient in the fabrick
of the chicken, that he employ skill, providence,
wisdom, goodness, and understanding far above
the capacity of our rational souls.”
7th. In respect to the part of the female
generative system at which fecundation takes
place, it appears most probable that in quadru¬
peds and the human species this change occurs
before the ovum reaches the uterus, or some
way in the course of the Fallopian tubes ;
perhaps most frequently in the upper part of
them. There is, however, probably some
variation among animals and in different cir¬
cumstances regarding this point. But while
we state this as the conclusion most consistent
with facts in the present state of our know¬
ledge, we ought not to omit the mention of the
more prominent facts by which it is opposed.
In some of the lower animals, fecundation
seems to extend beyond the sphere of the ova
which are ripe. In the Aphis (as was already
mentioned at an early part of the paper) the
production of young by the female goes on
for several generations (eleven) without any
sexual intercourse after that which gave rise to
the first. In the Daphnia Longispina this is
said also to be the case for twelve generations,
and in the Monoculus pulex for fifteen. The
queen-bee lays fruitful eggs during the whole
year after being once impregnated ; and in the
instance of the common fowl and some other
birds, previously referred to more than once,
if we reject the supposition of the seminal
fluid remaining in action, it seems necessary to
suppose that fecundation must occur in the
ovary, since unripe ova are acted on by the
fecundating medium at the same time with
those which are arrived at maturity and are
ready to descend into the oviduct.*
Many physiologists also believe that the
influence of the first impregnation extends to
the products of subsequent ones. Thus Haller
remarks that a mare which has bred with an
ass and has had a mule foal, when it breeds
next time with a horse, bears a foal having
still some analogy with the ass. So also in
the often cited instance of the mare which bred
with a male Quagga, not only the immediate
product, but three foals in subsequent breedings
with an Arabian stallion, and these three even
more than the first, partook of the peculiarities
of the Quagga species.
Instances of the same kind are mentioned
by Burdach as occurring in the sow and bitch ;
and it is affirmed that the human female
also, when twice married, bears occasionally to
the second husband children resembling the
first, both in bodily structure and mental
powers.
According to Hausmann, when a bitch has
connexion with several dogs (and this is gene¬
rally the case during the continuance of the
heat, sometimes to the amount of twenty,) she
usually bears two kinds of puppies at least, and
the greater number of these resemble the dog
with which she first had connexion.
We feel at a loss to decide what weight
ought to be attached to these observations ;
they appear to bear chiefly on the subjects
which are discussed in the next part of this
article.
V. MISCELLANEOUS TOPICS RELATING TO THE
PRECEDING HISTORY OF GENERATION.
We have deferred until now the consideration
of some topics which usually find a place in
the history of the generative function, as we
have thought it desirable to separate them from
the preceding narrative on account of the
vagueness of the facts and speculative nature
of the opinions with which they are connected.
The subject last discussed naturally leads to
* Burdach hazards the opinion that in some
quadrupeds the ova may not even be developed at
the time of impregnation, as in the Roe-deer, which
pair in July and August, but do not bear their
young till May, and the Fox, the period of gesta¬
tion in which is much longer than we should sup¬
pose it ought to be, judging from the analogy of
others of the Dog genus.
