NOTES AND ILLUSTRATIONS. 179 



The following extract is taken from the introductory part of Dr. Hosack's letter : 

 " The visiter or attendant contracts disease from one of two sources, either from the 

 filth of the sick room, or from a specific something issuing from the body of the sick, the 

 consequence of the peculiar disease under which he labours. If a person visiting auother 

 ill of the yellow fever, or plague, derives his disease from the impure atmosphere of the 

 apartment, I ask, how it happens, that in all instances he contracts the same disease with 

 that of the person whom he visits ? Why is his disorder not an intermittent , a remittent, 

 jail fever, or dysentery, which are considered the usual produce of filth ? If he derives 

 any thing specific from the sick, his disease is then assuredly not to be considered as 

 occasioned by the atmosphere, but depending on the peculiar condition of the fluids, or 

 state of the system, induced by the action of a specific poison ; in other words, it is to be 

 considered a contagious disease. The distinction proposed by Dr. Bayley, inasmuch as 

 it does not account for the communication of the peculiar form of fever or disease which 

 is thus propagated, I therefore consider to be insufficient to account for the circumstances 

 attending the communication of those diseases to which it is applied. That I may not 

 be misunderstood, I will suppose A to be ill of dysentery, a disease well known to be 

 attended with a. peculiar train of symptoms ; he is in a small confined apartment, his 

 person is neglected, the atmosphere around him is rendered impure and offensive ; under 

 these circumstances B visits him, and a few days after is also taken sick with the same 

 disease, attended in all respects with the same dangerous symptoms which characterize 

 the disorder of A. Dr. Bayley, and those who adopt the doctrine of infection as op- 

 posed to contagion, consider the disease of B to proceed from the impurities of the air 

 of the chamber, and not from any thing peculiar emanating or secreted from the body of 

 A. But as we may, without hazard, visit an equally filthy chamber where C lies ill of 

 cholera morbus, or D with a broken limb, I therefore ascribe the disease of B to some- 

 thing more than the impure air of the chamber of A. I ascribe it to a peculiar virus 

 generated in his system by the disease under which he labours, and communicated by his 

 excretions to the surrounding atmosphere, rendering it thus capable of producing the 

 same disease in those who may be exposed to its influence." 



Europe is already greatly indebted to that spirit of investigation which characterizes 

 the professors of the healing art in this country ; a spirit which has led to the overthrow 

 of many errors, and to the discovery of new physiological and pathological principles ; 

 which has prompted its professors to exertions that have eminently contributed to the 

 general adoption of a more judicious treatment of many disorders, to the rejection of 

 numerous inert substances inserted into the materia medica, and to the augmentation of 

 the list of those of approved medicinal virtues; to a more liberal use of vigorous remedies, 

 and to a more bold and successful method of practice. 



