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 foetus 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 plastical 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 foetus 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 readies 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 ;han we should sup- 

 pose it ought to be, judging from the analogy of 

 others of the Dog genus. 



