BIOGRAPHICAL SKETCH OF JOHN ADAM RYDER. 683 



aft poles, the axial differentiation, and a possible anterior sensory 

 apparatus of Volvox minor,' 1 ' 1 and in his paper on "The origin and 

 meaning of sex." These papers began a series which (included in the 

 bibliography under numbers 174, 180, 190, and 191) dealt not so much 

 with problems in dynamics as with the old vital doctrines, or, as would 

 be expressed in modern phrase, metabolism. "The origin and mean- 

 ing of sex" appeared in the Biological Bulletin, University of Pennsyl- 

 vania, 1889. Extensions of opinion were printed in the Proceedings of 

 the Academy, 1889, and in the American Naturalist, 1889, 501. lie 

 held that overnutrition led to all forms of sexual reproduction; that 

 the male and female elements are contrasted in their tendency to 

 undergo segmentation — the female element having lost the power to 

 undergo such segmentation spontaneously (excepting in parthenogen- 

 esis) — while the male element is accompanied by an increase of seg- 

 mental power. * * * "Sex probably arose simultaneously and inde- 

 pendently in both female and male as soon as certain cells of coherent 

 groups became overuourished and incapable of further segmentation 

 unless brought into contact and fused with the minute male element, 

 or one which is the product of an increase of segmentation al power 

 which is transferred to the female element in the act of fertilization." 

 Important applications were made of the hypothesis to the study of 

 variation, the evolution of sexual characters, and, as the author believed, 

 a consistent and simple theory of inheritance which is in harmony with 

 all the facts of reproduction. At this time he was in a state bordering 

 on exaltation. "I sat up late last night after the whole thing flashed 

 across my mind in an instant," he writes, "and did not sleep for two 

 hours after I went to bed because by brain was going like a dynamo, 

 thinking out detail after detail of my hypothesis. * * * Wolfe and 

 Schwann mark two eras in the history of hypothesis. I shall mark a 

 third if I live to complete the sketch of the vast hypothesis. * * * 

 My disappointments vanish into the uttermost inane when I think of 

 what it has been possible for me to achieve." 



After such strong evidence of his belief in the value of this theory, it 

 is hard to understand how he practically dropped the subject. Subse- 

 quent to the dates above given, I have come across no reference to it, 

 nor is any mention made of the matter in the estimates of his work that 

 have appeared since his death. 



It is impossible to understand Ryder's attitude toward evolution 

 without regarding his disbelief in the "cult" usually known as Weis- 

 mannism, which embraces the opinions that acquired characters can 

 not be transmitted, and that a portion of each organism is carried 

 unchanged from parent to offspring. He said, in his paper on sex, 

 "The hypothesis which assumes that the germ plasma is precociously 

 set aside in order to render it immiscible with the somatic plasma, and 

 therefore immortal, is based upon a fundamental error of interpreta- 

 tion of the facts of morphology." In another place, an address entitled 



