Success in Controlling Sex 
of the results with pigeons. These and 
two or three earlier experimental inves- 
tigations have been cited in a more 
recent publication by Dr. Riddle as 
having a common basis of agreement 
with his results, and with his theory of 
the causation of sex. 
The German biologist Richard Hert- 
wig and his pupils have succeeded in 
producing an excess of males from frog’s 
eggs, by allowing these eggs to become 
“overripe”’ (take up water) before they 
were fertilized. Dr. Helen Dean King 
at the Wistar Institute, Philadelphia, 
has done just the opposite. By drying 
toads’ eggs before they were fertilized 
she secured as high as 90% females. 
The results agree with those of Dr. 
Riddle, when it is remembered that he 
found male-producing pigeon eggs con- 
tained more water than did the female- 
producing eggs. Hertwig increased the 
water content of frogs’ eggs, and pro- 
duced males; while females were pro- 
duced when Miss King decreased the 
water content of toads’ eggs. 
Sex appears to have been controlled 
by Whitney in one of the lowest worms, 
and by Woltereck with a small crust- 
acean. Finally, there are some obser- 
vations on cattle, and Dr. Alexander 
Graham Bell’s work*® with sheep, which 
Dr. Riddle interprets in the light of his 
own work. 
The most notable thing about the 
studies that have been made on the 
doves and pigeons, and the thing that 
distinguishes these studies from prac- 
tically all others that lead in this direc- 
tion, is to be found in the systematic 
attempt to decide, in this most favor- 
able material, whether the sex-control is 
real or apparent. We have already 
indicated the results of the inquiry. 
SOCIAL APPLICATIONS 
The many theories about sex-control 
in man are usually based on observa- 
tions in other animals, but as some of 
the essential facts in man are not known, 
all attempts at sex-determination at 
163 
present are futile. But if Dr. Riddle’s 
work withstands the searching examina- 
tion which it is sure to receive as soon 
as it is published in full, and if it is 
agreed that sex is a plastic thing which 
can be changed by sufficient pressure 
(again speaking figuratively), then it 
would appear that sex-control in man 
is not so impossible as it has sometimes 
been thought to be in recent years. 
Apart from this very obvious appli- 
cation of a knowledge of sex-control in 
human society, the new idea of the 
nature of sex opens up some interesting 
possibilities to the eugenist. If the 
Whitman-Riddle observations on 
pigeons should be found substantially 
to hold good for man, we would be in 
the way of understanding the existence 
of so many masculine women and 
effeminate men in the world—the men 
and women who make up that “‘inter- 
mediate sex’’ of which much has been 
heard lately. 
Sex-conservation, perhaps, will be 
one of the future planks in the eugenics 
platform. As Dr. Riddle once pointed 
out, there are in this country probably 
more masculine women than feeble- 
minded individuals, and more effem- 
inate men than criminals. From a 
biological point of view, they are usually 
regarded as undesirable. “At present 
we look upon the appearance of the 
inadequately sexed individual as in- 
evitable; just as a generation ago we 
looked upon the presence of the feeble- 
minded as inevitable. But once we 
realize that sex—its kind and quantity— 
can be controlled, we are brought face 
to face with many new possibilities, and 
some new responsibilities, in this direc- 
tion. %* 
If the amount of sex possessed by a 
man or woman is partly dependent on 
the influences which surround the indi- 
vidual—on the environment, in short— 
perhaps we are making a mistake by 
throwing men and women into environ- 
ments which are constantly becoming 
3 See the JouRNAL oF HEREDITY, Vol. V, No. 2, pp. 47-57, February, 1914. Some of the 
other cases are described by T. H. Morgan in his book on Heredity and Sex (New York, 1913). 
4 This and the succeeding quotations are from Dr. Riddle’s paper on “The Determination _ 
of Sex and Its Experimental Control;” in Bull. of the American Academy of Medicine, Vol. XV, 
No. 5, October, 1914. Some of the material was also published in the Journal of the Nat. Inst. 
Soc. Sci., Vol. I, No. 1, pp. 39-42; December, 1915. 
