IO4 



PIONEERS OF SCIENCE IN AMERICA. 



the secrets of the cryptogamic class of plants. In the spring 

 of 1794 I also attended the public lectures of botany delivered 

 by the President of the Linnaean Society, Dr. (now Sir) James 

 Edward Smith ; and by the kindness of the same gentleman I 

 had access to the Linnaean Herbarium. I spent several hours 

 daily for four months examining the various genera and the 

 most important species contained in that extensive collection. 

 Notwithstanding my attention to botany, I was not unmindful 

 of the other departments of medicine." The acquaintance 

 thus begun with Sir James Edward Smith ripened into an affec- 

 tionate friendship, and a correspondence was begun that ended 

 only with Smith's life. 



In the course of the winter of 1 793-^4 Dr. Hosack em- 

 bodied certain Observations on Vision in a paper which he 

 communicated to the Royal Society. It was published in the 

 society's Transactions for 1794, and brought him, after due 

 examination by a committee, the thanks of the society. A 

 theory was in some vogue at the time that the power of ac- 

 commodation in the eye resided in the crystalline lens. Ho- 

 sack maintained the opposing theory, that it depended upon 

 the external muscles. His paper contained many original 

 views, and its statements were supported by experiments that 

 he had made upon himself and others. 



He returned to New York in 1794 by the ship Mohawk, 

 the passage lasting fifty-three days. On the voyage typhus 

 fever made its appearance and became very general, particu- 

 larly among the steerage passengers. Dr. Hosack being the 

 only physician on board, was called upon to attend the stricken 

 ones, and was wonderfully successful, not losing a single case. 

 His services were duly appreciated by all, as was evinced by 

 the unsolicited vote of thanks published in the daily papers 

 when the ship reached port. 



Taking up his residence in New York city, Dr. Hosack at 

 the age of twenty-five years began again the practice of his 

 profession under the most favourable auspices. Mr. Thomas 

 Law, who had been a fellow-passenger on the Mohawk, intro- 

 duced him to many of his acquaintances, among whom were 

 General Hamilton and Colonel Burr. He soon became the 

 family physician to these distinguished persons. In 1795 he 

 was appointed Professor of Botany in Columbia College, for 

 which position his diligent application to this science in Lon- 



