SYNGAMY AND SEX IN THE PROTOZOA 157 



in highly-organized forms, such as the Ciliata. Her twig (68) con- 

 siders that the separation of two kinds of chromatin is an adaptation 

 to particular conditions of life, evolved progressively, and attaining 

 its greatest perfection in the Ciliata ; whereby chromatin which 

 has become functionally effete is separated from that which has 

 retained its constitution. 



According to the view put forward by Hertwig (118), syngamy 

 remedies the effete condition of the cell chiefly by regulating the 

 necessary quantitative balance between the nucleus and the cyto- 

 plasm. Such regulation may be effected also by internal re- 

 arrangements of the nuclear substance or by plastogamy, but is 

 brought about most efficiently by syngamy, since the definite and 

 necessary mutual relations between nucleus and cytoplasm are 

 better maintained by " arrangements which prevent disturbance, 

 than by arrangements which compensate for disturbances that 

 have already set in." The obvious criticism of this theory is that 

 it is difficult to understand why an internal regulative process of 

 the cell should require the co-operation of two individuals, and the 

 reason contained in the sentence just quoted from Hertwig scarcely 

 seems an adequate explanation. 



The fact that two cells participate in syngamy indicates in itself 

 that the necessity for syngamy depends on a loss of balance between 

 two constituents or substances in the cell, and that the union of 

 the two gametes restores equilibrium. As Hertwig (119) has 

 pointed out, the quantitative relation of nucleus to cytoplasm is 

 more altered in the gametes of Metazoa than in any other cells, 

 and to opposite extremes in the two sexes ; in the ovum the quantity 

 of cytoplasm is enormous in proportion to the nucleus, while in 

 the spermatozoon the exact reverse is the case. The same argu- 

 ment applies to a greater or less degree in the case of anisogamous 

 gametes of Protozoa. It would not, however, apply to the many 

 cases of isogamy in Protozoa where the quantitative relations of 

 nucleus and cytoplasm are the same in each gamete ; in such cases 

 union of the gametes would leave the nucleo-cytoplasmic relation 

 exactly what it was before. 



A theory of a different kind has been put forward by Schaudinn 

 (133) and his followers Prowazek (128) and Hartmann (116), 

 which is based on the notion that sex and sexual differentiation 

 are primary characteristics of living matter. A normally function- 

 ing cell is regarded as hermaphrodite, having male and female 

 elements equally balanced. The differentiation which leads to 

 the formation of gametes arises, as Biitschli originally suggested, 

 from inequalities in the results of cell- division, which may be 

 supposed to lead always to more or less imperfect partition of the 

 qualities of the parent-cell between the daughter-cells, As a result 



