1896.] NATURAL SCIENCES OF PHILADELPHIA. 237 



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 contemporary literature, and 

 nothing appeared to give him so much pleasure as talking of the 

 work of his co-laborers ; 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 resprct 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 attain- 

 ment 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 his apparent obstinacy of disposition as a child ; 

 his aversion to class work at school ; and his independence of con- 

 vention, both as to thought and action in mature life. 



Sometime prior to his appointment on the Fish Commission, Mr. 

 W. V. McKean invited him to write articles on natural history for 

 the Public Ledger. But Ryder could not overcome a distrust 

 that his essays would be too technical for popular favor. That he 

 should have declined an oflfer apparently so advantageous to himself 

 at a time when he needed money, is an evidence of the rigid scrutiny 

 to which he subjected all his actions. None but his most intimate 

 friends knew of the costs he often paid to maintain his freedom 

 of mental action. They were met without a murmur. But in their 

 payment he doubtless drew largely on that vital energy, without 

 which long life is impossible. His dearest friend said of him, " his 

 self-sacrificing devotion cost him his life." 



But, under the stern repression lay a child-like, affectionate 

 nature. He was not happy unless he had one or more of his family 

 with him ; he was continually writing to the absent ones. His 

 domestic letters contain full accounts of how he lived, whom he met, 



