Proceedings of the Cambridge Philosophical Society Volume 13-14; Mathematical and Physical Sciences (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1906 Excerpt: ...that she possesses it. But if it is so, that is no evidence that the ovum from which she is derived requires more nourishment for its development. Again, the greater difficulty experienced in rearing male than female children is attributed by some observers to the better nourished condition in which girls are born; and many have argued, in one form or another, this is clear evidence that the mother needs an extra supply of nourishment to enable her to produce a girl. So far as this latter point is concerned perhaps the greater mortality among male infants is otherwise to be explained. But however this may be the point at issue is not affected thereby, for if nutriment has any effect at all upon the proportion of the sexes produced, it must be exerted on the ovum in the ovary; that is to say it is the capacity of the mother to supply the ovary with nutriment which must be taken into consideration. Now it does not at all follow that a female with exceptional powers of assimilating and of storing nutriment, or that a mother especially capable of producing well-nourished offspring, gives birth to an excess of females; indeed my own experiments indicate that the reverse, in many cases, is true. At the same time there are records of experiments which may, in my opinion, be interpreted to show that nutrition has a selective action on ovarian ova; it is on these lines I have myself been working, not without success; and I hold that either quantitatively or, more probably, qualitatively this is true. Of the various other agencies which it is claimed affect the proportion of the sexes born, such as in-breeding, cross-breeding, age, climate, temperature, &c.; such power as they have, and I think there is sufficient evidence to show they are potent agencies, must b...