1890.] 155 [Ryder. 



16. The male cell as a consequence of the reduction of its cyloplasmic 

 field at last became incapable of further independent development. 



17. The male and female elements became reciprocally attractive to one 

 another (sometimes through the production of certain chemical substances 

 in the vicinity, PfefFer), and in that their idioplasm is less different from 

 one another than that of other cells there is no bar to their fusion, which 

 is also favored by the fact that in the male cell with its preponderant 

 Chromatic there is now an attraction or need developed for more cyto- 

 plasm similar to its own diminished quantity, while conversely there is a 

 similar need or attraction developed in the egg for additional chromatin in 

 consequence of its preponderating cytoplasm. This leads to the highest 

 form of cumulative integration through direct fusion of the male and 

 female elements, or what I shall call reciprocal integration without loss of 

 molecular identity, or as it is commonly called, to "fertilization." "Fer- 

 tilization" is a reciprocal restoration of the equilibrium between the 

 chromatin or nucleoplasm and the cytoplasm of both ovum and spermato- 

 zoon, this takes place not with accompanying molecular disintegration 

 but by the actual fusion of both elements without the sacrifice of the 

 molecular identity of either. Mutual digestion is not possible, for both 

 elements are already composed of similar molecules. This molecular 

 similarity constitutes the means through which the hereditary traits and 

 tendencies of the male and female are transmitted. 



18. The accumulation of cytoplasm in the egg through cumulative in- 

 tegration has enlarged its cytoplasmic field beyond that of any cell of the 

 parent body. The result is that when "fertilization" occurs or fusion 

 with the male cell, a series of segmentations are set up in this mass which 

 ftre independent, and under the influence of new conditions, lead to the 

 continuation of growth as the development of an embryo. This develop- 

 ment is rendered directly possible only in virtue of the fact that there is a 

 large cytoplasmic field in which nuclear motion and growth can take 

 place in three dimensions temporarily without access of nutriment, while 

 the resulting segmentations are coherent and tend to take place in such 

 order and relation as to produce a being similar to the parent. The aggre- 

 gation of large masses of segmentable plasma through the operation of 

 cumulative and reciprocal integration has enabled the products of such 

 simultaneous and successive segmentations to cohere and remain a multi- 

 cellular aggregate, and to lay the foundation and become the direct cause 

 of all metazoan and metaphytic organization. 



19. The augmentation of the mass of the egg through cumulative inte- 

 gration and the development of the ob'sperni through reciprocal integra- 

 tion, has rendered possible the development of embryos without need of 

 other nutriment during the preliminary or larval stages of ontogeny, thus 

 leading also to the evolution of all larval forms, through processes of 

 direct adaptation. 



20. The achievement of the multicellular condition is probably to be 



