Bauhaus-Universität Weimar

Titel:
The Cyclopaedia of Anatomy and Physiology, vol. 2: Dia-Ins
Person:
Todd, Robert Bentley
PURL:
https://digitalesammlungen.uni-weimar.de/viewer/image/lit25760/476/
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.
        

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