42 INTRODUCTION. 



In 1816, a new topic of inquiry was presented here, as well as in Europe, 

 involving the question whether the human system was susceptible of the yellow 

 fever a second time. Dr. Francis, then in London, addressed a letter of inquiry 

 on the subject to the medical faculty of the United States ; and the result of the 

 testimony acquired, seemed to show that, after one visitation, the constitution has 

 generally an exemption from that disease. Dr. Townsend, in his treatise on the 

 yellow fever as it manifested itself in 1822, corroborated this conclusion ; but 

 after all, on a point of such deep interest to humanity, further inquiry seems 

 desirable. 



Dr. Hugh Williamson's " Observations on the climate in different parts of 

 America, compared with the climate in corresponding parts of the European con- 

 tinent," is a work of much interest. His exposition of the meliorating effects of 

 cultivation of the earth upon the temperature of the country, is very cheering to 

 the philanthropist. The disquisitions of Dr. Samuel Forry, on the climate of 

 the United States, and its endemic influences, challenges the attention of the 

 philosopher as well as of the physician. 



A disease designated by several names, as "spotted fever," "malignant typhus," 

 "typhoid pneumonia," and other appellations, prevailed extensively in 1812 

 and 1813. Monographs on this pestilence were given to the public by North, 

 Hosack, Hudson, Arnell, and several other contributors to the New- York Medical 

 Repository, and to other periodical journals. 



The appearance of the cholera asphyxia, in 1832, at New- York and at Albany, 

 and shortly afterwards its extensive ravages in other parts of this state, and the 

 United States, awakened medical ardor, and the new enemy was encountered 

 with energy and with clinical acumen. It numbered four thousand victims in New- 

 York, and was proportionably not less fatal in Albany. Francis, Paine, McNaugh- 

 ton and Reese were distinguished by their examinations into the origin and nature 

 of the disease. It is deeply to be regretted that we are still without a direct and 

 perfect history of this, and the various other epidemics which have prevailed at 

 different periods. The influenza spread over our territory in 1807, in 1811, and 



