HOSACK ON THE LAWS OF CONTAGION. 217 



but the cases are never so bad nor nearly so frequent, as towards the end 

 of summer ; they then become epidemic and contagious. They have 

 always been most numerous and worst after hot and close summers, espe- 

 cially in fixed camps, or when the men lay wet after a march in warm 

 weather."* " In general the contagion does not suddenly spread ; for 

 whole towns and camps are never seized at once from the impurities of the 

 atmosphere ; but the infection is carried from one to another by the efflu- 

 via, or clothes and bedding, &c. as in the plague." " In camps the conta- 

 gion passes from one who is ill to his companions in the same tent, and 

 from thence, perhaps, to the next." " The foul straw," he adds, " be- 

 comes infectious, but the greatest sources of infection are the privies, after 

 they have received the dysenteric excrements of those who first sicken. 

 The hospitals likewise spread it, since those who were admitted with the 

 flux not only gave it to the rest of the patients, but to the nurses and 

 other attendants of the sick."t And to show that this disease is not- 

 dependent on a general constitution of the atmosphere, but upon that 

 which is impure, and to which the dysenteric taint has been communi- 

 cated, he observes of the epidemic which raged at Nimeguen, in 1736, 

 <* that none of the neighbouring towns suffered, unless by their commu- 

 nication with the place infected.":}: Similar facts, illustrative of the 

 rapid extension of this disease, when introduced into ships of war, are 

 recorded by Dr. Blane, in his valuable work on the Diseases of Seamen. 

 That the contagiousness of typhus fever is, also, in a great degree, 

 ascribable to a similar condition of atmosphere as its pabulum, is demon- 

 strated by facts recorded in almost every book of practice, more espe- 

 cially in those relating to the diseases of the army and navy, which have 

 ever been found to be nurseries of this disease. The observations made 



* Diseases of the Army, p. 218. ed. 7th. f Ibid. 254, \ Ibid. 252. 



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