BIOGRAPHICAL SKETCH OF JOHN ADAM RYDER. 685 



are at the bottom of the whole matter. Some day I shall be able to 

 tell a great deal that I have kept to myself in order to test its truth. 

 * * * I am engaged — and will be hereafter almost en tirely — in d eter- 

 mining the factors and processes which have effected the evolution and 

 divergence of species. * * * I have at last worked out a new theory 

 of inheritance which must ultimately replace those of Weismann and 

 Darwin, or at least furnish the foundation by which the data and phe- 

 nomena of variation and inheritance can be coordinated with the great 

 universal principle of the doctrine of the conservation of energy. The 

 speculations of Darwin, Haeck el, Weismann, Brooks, DeBries, Strass- 

 burger, and Nageli looking to a theory of inheritance are irreconcilable 

 with the fundamental postulates of physical science, and must be aban- 

 doned. This also renders the conflict between the hy pothesi s of Darwin 

 and those of Lamarck one of primary importance, and sharply defines 

 the line of battle between the thinkers who range themselves under the 

 banner of one or the other of these prophets of transformism. 



While it is impossible to say what Dr. Ryder would have accomplished 

 in his attempt to use mathematics as a medium of expression of biolog- 

 ical problems, this much can be said, not only for him, but for all others 

 similarly placed, that a course of training in geometry and the higher 

 mathematics should be a part of the equipment of the student in biology. 

 It does, indeed, seem pitiable that, ascending the heights of knowledge, 

 he finds, as he nears the top, that the key which he believes can alone 

 open the temple erected there has been left behind. 



III. 



Dr. Ryder was 5 feet 11 inches high, of a slender, slightly stooping 

 figure. While spare, he had a robust physique. He was of nervous 

 temperament. His complexion was light — the hair flaxen. He was 

 plain — almost careless — in his dress. He had a habit of sitting cross- 

 legged and swinging one foot when deeply engaged in thought or study. 

 He was of a genial disposition and enjoyed gatherings with his students 

 after class hours, or discussions with his colleagues and friends at the 

 academy and other places. His learning was great, especially in con- 

 temporary literature, and nothing appeared to give him so much pleasure 

 as talking of the work of his colaborers; but he disliked what are called 

 " social functions," and toward the latter part of his life was rarely 

 present at them. From the beginning of his scientific career to his 

 later years he did not require much sleep, taking about six hours daily, 

 though his habits in this respect were never regular. He had great 

 energy of mind, and power of accomplishing a large amount of brain 

 work. His memory was remarkably retentive — he never forgot anything 

 he once heard or read. In addition to his early attainment of German, 

 he read, for scientific purposes, French, Italian, Spanish, Dutch, Danish, 

 Swedish, and Russian. 



His sense of duty was highly developed. He believed that the power 

 of the will over action was practically without limit. Yet the motive 

 for the exercise of the will must be from within. Hence can be explained 



