21 i> HOSACK ON THE LAWS OF CONTAGION. 



upon this subject by the Linds, Pringle, Blane, Percival, Smyth, Trot- 

 ter, Haygarth, Ferriar, Currie, and others, relating to the spread of this 

 disease, when introduced into hospitals and ships of war ; its prevalence 

 and diffusion among the poor of London, Edinburgh, Liverpool, and 

 the manufacturing towns of Great Britain ; the beneficial effects which 

 have been derived from the establishment of fever Avards, and houses of 

 recovery, the advantages which have been experienced from the fumigat- 

 ing or oxygenating processes introduced by Dr. Johnstone of Worces- 

 ter, Guyton De Morveau, and Carmichael Smyth, in arresting the pro- 

 gress of the typhus fever, all irresistibly lead to the conclusion, that the 

 impurities of the air constitute the fuel of this disease ; and, to use the 

 expressive language of Dr. Ferriar of Manchester, in a late communica- 

 tion which I have received from that learned physician, that " dilution 

 with atmospheric air is now ascertained to be the most effectual mean 

 of destroying contagion, and of controlling the ravages of this disease."* 

 Were it necessary, I might adduce a volume of additional testimony 

 on this subject. I cannot, however, omit the following pertinent re- 

 mark of Dr. Haygarth, who, like another Howard, has devoted his life to 

 the investigation of this interesting subject; and to whom Great Britain 

 is indebted for the first establishment of institutions specially devoted to 

 the important purpose of arresting the progress of contagious diseases. 

 In his remarks on the nature of the contagion which produces putrid 

 fevers, he observes, " I soon discovered that their infectious atmos- 

 phere was limited to much narrower extent than even the small pox. 

 So manifestly I observed this to be the case, that in a clean, well- 

 aired room, of a moderate size, the contagious poison is so much 

 diluted with fresh air, that it very rarely produces the distemper, even 

 in nurses exposed to all the putrid miasms of the breath, perspiration, 



* See American Med. and Phil. Register, vol. 2. 



