1879.] * J ^" [Brinton. 



Obituary N once of the late Isaac Hays, M.D. By Daniel G. Brinton, M.D. 

 {Read before the American Philosophical Society, May 16, 1879.) 



The subject of the present memoir, Dr. Isaac Hays, had been at the time 

 of his death, a member of this Society for very nearly fifty years, his name 

 first appearing upon its rolls in 1830. For many years he was also one of 

 its most active members, and in the published volumes of our Proceedings 

 which embrace the period previous to 1850, his name frequently recurs. 

 Most of the subjects which he brought before the Society, related to medi- 

 cal science, and especially those portions of it connected with the physi- 

 ology of vision and ophthalmic surgery. But he did not confine himself to 

 professional topics. I find, on looking over the earlier numbers of our Pro- 

 ceedings that he took considerable interest in geology, particularly in the 

 remains of the gigantic mammals preserved from the post-tertiary period. 

 About 1840, a number of such remains were collected in Missouri by Dr. 

 Koch, and subsequently exhibited in this city and London. An active dis- 

 cussion arose among palaeontologists as to their classification. Besides, the 

 mastodon, the Elephas primogenius, and the mammoth, they distinctly 

 proved, so one party maintained, the former existence of another species of 

 mastodontoid animals belonging to the class Proboscidw, to which was given 

 the name Tetracaulodon. Dr. Hays sided with this party, and in addition 

 to many verbal statements embodied in the Proceedings, he published in 

 the Transactions a paper on the teeth of the mastodon, evincing in its 

 preparation a most careful study of his theme. That later investigations 

 have disproved his position, detracts but little from its merit ; for the ab- 

 stract correctness of a scientific theory is of less importance than the 

 honesty and ability with which it is advocated. At various periods Dr. 

 Hays served on the Committee of Publication, and the Council, and was 

 Curator. 



At the time Dr. Hays was elected to this Society, he was thirty-four 

 years of age. He was born July 5, 1796, in this city, his father residing at 

 that time on Chestnut street below Third. His education had been first at 

 the Grammar school kept in those days by Samuel Wylie, next at the Uni- 

 versity of Pennsylvania, whence he was graduated, A. M., in 1216 ; and 

 finally as a medical student in the same institution whence he received the 

 degree of M. D., in 1820. His preceptor was the eminent Dr. Nathaniel 

 Chapman, celebrated not less for his wit than for his professional skill. 



In early life Dr. Haj's was much interested in natural science, and even 

 before his graduation in medicine, he joined, in 1818, the Academy of Natu- 

 ral Sciences. With its history and success, he was identified for more than 

 half a century. From 1865 to 1869 he was its President, and in many other 

 official capacities actively aided its progress and influence. 



His sympathies with the advance of general science led him to unite with 

 others in the organization of the Franklin Institute. He was one of its 

 original members, and for a number of years Its Corresponding Secretary. 



