PHYSICAL AND LITERARY.419 



gated by contagion in the air, diftinguifh- 

 ed from that infecflion which is commu- 

 nicated by morbid bodies, as in the finall 

 pox and malignant fevers. With regard 

 to this, we can only form an indetermi- 

 nate notion of a deleterious aura, waft- 

 ed about every where, and afFedling num- 

 bers luddenly, in different places at the 

 fame time. From no manifeft qualities 

 in the air, its heat, cold, moifture, or dry- 

 nefs, is the caufe to be deduced ; confe- 

 quently, no good rule of pradlice can be 

 eflablifhed in reference to thefe. 



It feems to be the genius of the di- 

 flemper, to exert its ftrength chiefly on 

 the lining membrane of the nofe, fauces, 

 and trachea, the eyes, and, more or lefs, 

 the glands about the jaws and throat,cau- 

 ling fometimes confiderable tumor. Nei- 

 ther, for this, can we aflign a reafon. a- 

 ny more than why mercury fo conftantly 

 aflfe<5ls the falivary glands, often with ex- 

 cefllve tumour, in fome fort, refembling 

 that fpecies of catarrh, with us termed 

 the Branks, in the other part of our 



ifland, 



