258 Proceedings of the Royal Physical Society. 
and the cytoplasm arose in the sexual products of the two 
sexes respectively.” 
An ovum is a “large overgrown type of cell, loaded with 
cytoplasm and its secondary products”; in its production 
“there occurs a prolonged process of integration of plasma” ; 
the result is “an enormous cytoplasmic field, in the midst 
of which there is placed a large nuclear body containing, 
proportionally to its envelope of cytoplasm, a very small 
amount of chromatin.” Jn short, in the reproductive cell 
produced by a female, there 1s a preponderance of cytoplasm 
over chromatin. 
A spermatozoon is a very minute type of cell, “ consisting 
mainly of plasma in a highly anabolic condition as chromatin,” 
“ characterised by the absence of a cytoplasmic field, in which 
nuclear motion, or karyokinesis, can occur”; “the elaboration 
of the chromatin in the male clearly takes place in some 
cases at the expense of cytoplasm”; “in consequence of the 
reduction of its cytoplasmic field, it becomes incapable of 
further independent development”; “in the production of 
male elements an actual process of elimination of cyto- 
plasm often occurs, so as to reduce the latter to a 
minimum, and leave little remaining except the nucleus 
and its chromatin.” Jn short, wm the reproductive cell 
produced by a male, there 1s a preponderance of chromatin 
over cytoplasm. 
[So far an introductory statement of the contrast between 
the sex-cells, according to Ryder. He makes an important 
criticism of “The Evolution of Sex,” when he says: “The 
view that the female is preponderatingly ‘anabolic, and the 
male ‘ katabolic, as held by Geddes and Thomson, cannot be 
sustained on the basis of fact, since it is readily demonstrated 
that the male element represents a higher product of con- 
structive metabolism than the female.” 
To this it may be replied:—(1) That the theory of sex 
proposed in the “Evolution of Sex” does not rest on 
an interpretation of the reproductive cells alone, but of 
many other facts; (2) that several statements in the work 
cited are insufficiently precise, and require to be compared 
with other parts of the book, and require to be corrected in 
terms of what we have noticed above; (3) that although we 
