( 4§4 ) 
[August, 
ANALYSES OF BOOKS. 
The Law of Sex : being an Exposition of the Natural Law by 
which the Sex of Offspring is controlled in Man and the 
Lower Animals, and giving the Solution of various Social 
Problems, with Forty Illustrative Portraits. By G. B. 
Starkweather, F.R.G.S. London : J. and A. Churchill. 
The author of this work propounds a law, which if capable 
satisfactory demonstration is of very great biological value. Not 
confining himself to pure science, he has also an eye to practical 
applications, and believes that among the results brought about 
by the publication of his work will be “ the possible assimilation 
of alien and lower races, and the avoidance of a lamentable re- 
dundancy of women in old settled countries.” 
In forming an estimate of the work — or rather of the theory 
which it expounds — we have to deal with the double question : 
Is the proposed law valid? and, admitting such validity, will 
its practical recognition lead to the results which Mr. Starkweather 
hopes ? 
The primary problem is this : Given a pregnant female animal, 
what will be the sex of her offspring ? 
Before stating his own reply the author reviews certain existing 
opinions. Thus we are told by some that the parent which at 
the moment of conception is the more impassioned impresses its 
sex on the offspring. The older theories of sex, are rightly 
enough, described as “ chiefly ovularian or spermatic, with 
various theories of development superadded, such as those of 
epigenesis, metamorphosis, and syngenesis.” A vague popular 
notion is that the will or the imagination of the mother deter- 
mines sex. Dr. Naphreys puts forward a hypothesis which has 
a more scientific appearance. He maintains that every ovum 
passes through two distinCl phases of development. If it is 
fecundated during the former stage the offspring will be female, 
but if during the latter male. This view, however, is not 
supported by recent observations. The author further asks, 
acutely enough, “ How would this theory apply to twins, or to 
multiparous animals where there may be representatives of each 
sex produced at a birth?” We must here, however, quote a 
passage as indicative of his habits of thought : — “ Would it not 
be positive confusion if Nature has, as Dr. Hough maintains, 
given but six days per month in which females can be conceived 
— and if in the last two or three of these they must be insufferable 
viragoes ; and to the males has allotted as many more days — on 
