684 BIOGRAPHICAL SKETCH OF JOHN ADAM RYDER. 



"Dynamics in evolution," 3893, he said: "Experimental investigations 

 in embryology will make no solid progress until the mischievous influence 

 of such speculations have been eradicated from the minds of the present 

 generation." These opinions remained unmodified to the day of his 

 death. Perhaps the best expression of his views can be found in a 

 lecture delivered at Woods Hole, 1894:, and a second lecture, entitled 

 "A dynamical hypothesis of inheritance." 



The last phase of his scientific life is the most instructive, namely, 

 that relating to the application of geometery and the differential cal- 

 culus to the study of organic forms. The idea that anatomy and mathe- 

 matics can be of mutual assistance generally comes to savants too late 

 for practical use. Against the example of Helmholtz we cite many 

 failures. Mathematics came to John Goodsir too late for anatomy, and 

 anatomy to Fechner too late for mathematics. When Ryder saw the 

 necessity of preparing himself in these sciences (for his early training 

 had excluded them), he set to work to supply the defect with character- 

 istic energy. He studied geometery and the calculus in spare hours. 

 He became enthusiastic for them. He declared geometry to be the 

 noblest of the sciences. He read the writings of Lord Kelvin carefully; 

 his admiration for them was unbounded. At the time of Eyder's death 

 two works lay on the bed; one was a text-book on the differential cal- 

 culus, the other a volume of Lord Kelvin's works. 



It is difficult to fix a time when the mathematical explanation of the 

 mechanics of evolution occurred to him. We have seen that he was 

 influenced by Haughton as early as 1874. If we can draw an inference 

 from the reading of the paper entitled "The fore and aft x^oles of 

 Volvox minor," previously quoted, and, again, the essay "The polar 

 differentiation of Volvox minor'''' and " Specialization of possible anterior 

 sense organs" (No. 174, Bibliography), the idea apparently suggested 

 itself by studies in the early Academy days on the infusoria, and later 

 on the development of simple organisms. The same conception occurs 

 in his papers on "Energy in biological evolution;" "Of the represen- 

 tation of the relative intensity of the conflict between organisms;" 

 "Energy as a factor in organic evolution;" "Mechanical genesis of the 

 form of the fowl's egg', v " The adaptive forms and vortex motions of the 

 substance of the red blood corpuscles of vertebrates ; " "The correla- 

 tion of the volumes and surfaces of organisms." J One of the last demon- 

 strations he made was at a meeting of the Bibliographical Club of the 

 University of Pennsylvania, when he exhibited contractile films of gela- 

 tin in illustration of the mechanical conditions underlying the problem 

 of the arrangement of the convolutions of the brain. 



In January, 1890, he writes: 



It is my hope to reduce the doctrine of evolution into a simple realiza- 

 tion of Newtonian principles. The three great Newtonian laws of motion 



' See Bibliography, Nos. 182, 184, 186, 187, 189, and especially Nos. 190, 191, 192, 195, 

 199, 200, 204, 205, 206, and 207. Proc. Acad. Nat. Sci., Phil., April, 1896. 



