1890.] 147 [Ryder. 



tional properties of the plasma of egg and sperm, developed as a conse- 

 quence of the physiological division of labor in the cell between cytoplasm 

 and chromatin. The former is the immediate agent of intussusception, 

 the latter controls and coordinates the processes of the former. The one 

 is produced in a confined place tending to repress segmentational activity 

 or nearer abundant supplies of nutriment. The other is produced in open 

 cavities which admit of the free escape of sex products, or in regions, or 

 at times when the determination of pabulum is less abundant than in the 

 case of ova. Looking over the arrangement of the reproductive organs 

 and their relation and proximity to the nutritive system, in many forms 

 these views will be found to have much evidence in their favor. Never- 

 theless there is no evidence in favor of the one process being more kata- 

 bolic than the other. They are equivalent, only that in the ovum there is 

 a repressed segmentational tendency, in the spermatogonium an unre- 

 pressed one. The tendencies are towards the male or primitive monadi- 

 form condition in both, only that secondary physiological influences are 

 repressive in the female and irrepressive in the case of the male element. 

 Segmentation into spermatozoa is hindered in the egg, favored in the case 

 of the spermatogonium. Yet despite this there is not the slightest evi- 

 dence that the results in the two cases are not equivalent so far as the 

 expenditure of energy is concerned. 



The real difference in the result lies in this, that in the female element 

 there is an enormous cytoplasmic field in which simultaneous and succes- 

 sive nuclear movement can take place leading to the realization of a cohe- 

 rent process of development instead of an incoherent one such as occurs 

 in the breaking down of the spermatogonium into spermatozoa. The 

 process in the one case is cohesive, in the other disruptive and self-de- 

 structive. The tendency then in the female is towards morphological in- 

 tegration, in the male towards morphological disintegration, but upon the 

 common basis of the spermatogonium. 



The real gain of this is not in the absolute bulk of the embryo simply, 

 but in that such an embryo may become self-mobile and self-helpful in 

 spite of its size. Herein lies the true significance of sex and of the cumu- 

 lative process initiated through the repression of the primitive segmenta- 

 tional tendency of the spermatogonium. An embryo thus developed can 

 go through an entire and elaborate cycle of embryonic development with- 

 out requiring to take food at all and attain to a self-helpful, self-mobile 

 condition. 



It is therefore obvious that in such a process of repression of segmenta- 

 tion of the spermatogonium there has been a distinct advantage gained in 

 the struggle for existence, in that such a spermatogonium could directly 

 become the means by which a rapid or saltatory process of evolution 

 could be accomplished, resulting in the evolution of larval forms. From 

 such a stepping-stone the hypertrophied spermatogonium — ovum — other 

 advances were possible, especially in the direction of variation, since such 

 rapid simultaneous and successive segmentations would provide the most 



