1919] STOUT—INTERSEXES 129 
processes of growth, development, and interaction of tissues, and 
subject to modification or even complete determination by them. 
The older conception of mystical properties of maleness and 
femaleness have given place to what are fundamentally meta- 
bolic theories of sex determination. ‘The principal points of dif- 
ference in the large number of theories, thus to be grouped, lie in 
questions regarding (1) time of determination, (2) whether the two 
sexes are two contrasted conditions or simply phases of the same 
general property, (3) to what extent sex development in the indi- 
vidual is an evolution or an epigenesis, and (4) to what extent a 
physical basis can be related to differences in the amount of chro- 
matin present. 
To DARWIN and many of his contemporaries the evolutionary 
and adaptational significance of variations in sex were points of 
principal interest. That such variations fundamentally involve 
physiological processes operating in the organism was of course 
recognized. The increased femaleness seen in females of certain 
gynodioecious species was considered by DARWIN as involving the 
principle of compensation; with decreased expenditure of energy 
in development of male organs there was a greater supply for 
development and function of female organs. The doctrine of 
conservation in expenditure for useless organs was likewise ap- 
plied to the tendency to gynomonoecism as seen in such a species 
as P. lanceolata (LupwiG 19); the stamens in the uppermost 
flowers of a spike tend to be useless, and this was supposed 
to induce their elimination. The tendency to poor development 
of flowers at the tips of spikes, however, may be purely the result 
of food supply being diverted for use of lower flowers, and as 
such may be on quite a different physiological basis from the 
condition that makes an individual only female. The intimate 
association of many proterogynous flowers in a spike, however, 
may well give opportunity for changes in metabolic processes 
(RippLe) or influence of hormones (LILuIe). 
A very interesting and suggestive conception which has fre- 
quently been proposed is embodied in the view that maleness is a 
“katabolic habit”? of body (we may now add of an organ) induced 
by preponderance of waste over repair, and that femaleness is an 
