894 GENEKATIOST. 



number of males, and vice versa; but no exact laws of this kind have been found applica- 

 ble to the human subject. The idea that one testicle produces males and the other, 

 females, or that the two ovaries have distinct functions in this regard, has no foundation 

 in fact ; for men with one testicle, or females with a single ovary, produce offspring of 

 both sexes. 



Two ideas with regard to the determination of sex in the foetus have obtained at dif- 

 ferent times. One of these is that the sex is dependent upon nutritive or other con- 

 ditions subsequent to fecundation, and the other, that the sex is determined at the time 

 of union of the male with the female element. Of these two opinions, the weight of 

 evidence appears to be in favor of the latter. Aside from facts in comparative physiol- 

 ogy, it is pretty certain that several spermatozoids are necessary for the fecundation of 

 a single ovum. It may be that, when just enough of the male element unites with the 

 ovum to secure fecundation, or when it might be said that the female element predomi- 

 nates, the faatus is a female, and when a greater number of spermatozoids unite with the 

 vitellus, the male sex is determined. Such an idea, however, is purely theoretical ; and 

 the question of the determination of sex presents thus far hardly the shadow of a satis- 

 factory explanation. 



No definite rule can be laid down with regard to the transmission of mental or physi- 

 cal peculiarities to offspring. Sometimes the progeny assumes more the character of the 

 male than of the female parent, and sometimes the reverse is the case, without any refer- 

 ence to the sex of the child ; sometimes there appears to be no such relation ; and 

 occasionally we note peculiarities derived apparently from grandparents. This is true 

 with regard to pathological as well as physiological peculiarities, as in inherited tenden- 

 cies to certain diseases, malformations, etc. 



A peculiar, and it seems to be, an inexplicable fact is that previous pregnancies have 

 an influence upon offspring. This is well known to breeders of animals. If pure-blooded 

 mares or bitches have been once covered by an interior male, in subsequent fecun- 

 dations the young are likely to partake of the character of the first male, even if they be 

 afterward bred with males of unimpeachable pedigree. What the mechanism of the 

 influence of the first conception is, we can form no definite idea; but the fact is incon- 

 testable. The same influence is observed in the human subject. A woman may have, 

 by a second husband, children who resemble a former husband, and this is particularly 

 well marked in certain instances by the color of the hair and eyes. A white woman who 

 has had children by a negro may subsequently bear children to a white man, these chil- 

 dren presenting some of the unmistakable peculiarities of the negro race. 



Superfecundation of course does not come in the category of influences such as we 

 have just mentioned. It is not infrequent to observe twins, when two males have had 

 access to the female, which are entirely distinct from each other in their physical char- 

 acter ; a fact which is readily explained by the assumption that two ova have been 

 separately fecundated. This view is entirely sustained by observation and experiment. 

 Cases illustrating this point are numerous, but we cite one, simply to add to the number 

 of positive observations. 



The following very interesting communication was received in January, 1869, from 

 Dr. John H. Janeway, Assistant Surgeon U. S. A., and it illustrates Superfecundation in 

 the human subject ; or, at least, that was the view taken by the negro father: 



" Frances Hunt, a freedwoman, aged thirty-five years, gave birth to twins, February 

 4, 1867, in New Kent County, Virginia. One of these twins was black, the other was 

 white. Frances is a mulatto. The black child is much darker than she is. Previous to 

 the parturition, she had given birth to seven children, all single births. She was living 

 at the time of her impregnation in the family of a white man as house-servant, sleeping 

 with a black man at night. She insists, however, that she never had carnal intercourse 

 with a white man. She probably does this because the black man turned her out of his 

 house when he saw that one of the children was white." 



