THEORY OF SEX— ITS NATURE AND ORIGIN. ny 



In active, motile, ciliated, or flagellate cells, whether they be 

 constant forms or only temporary phases, there is predominant 

 katabolism, — predominant when compared with the life-expenditure 

 of a passive, quiescent, enclosed, or encysted cell. In amoeboid 

 organisms these extremes are avoided; there is certainly great ampli- 

 tude of variation still, but neither anabolism nor katabolism gains the 

 ascendant in any marked degree. 



Suppose, then, in such an amoeboid cell, a continued surplus of 

 anabolism over katabolism, the result is necessarily a growth in size, 

 a reduction of kinetic energy and movement, an increase in potential 



Fig. 36. — Diagram showing the divergence of ovum and spermatozoon 

 from a undifferentiated amoeboid type of cell. 



energy and reserve food-material. Irregularities will tend to disappear, 

 surface-tension, too, may aid, and the cell acquires a spheriodal form. 

 The result — surely intelligible enough — is a large and quiescent 



ovum. 



It will be remembered that young ova are very frequently amoeboid; 

 that with a copious nutrition this disappears in varying degrees of 

 encystment; that ensheathing envelops arising from the ovum, sweated 

 off like cysts round Protozoa, are exceedingly common; and that ova 

 are the largest of all animal cells. 



Starting once more from an amoeboid cell, if katabolism comes to 

 be more and more predominant, the increasing liberation of kinetic 

 energy thus implied must find its outward expression in increased 

 activity of movement and in diminished size; the more active cell 



