RELAPSING FEVER 151 



quite independent of climatic conditions, relating 

 rather to circumstances connected with the mode 

 of life and hygienic surroundings of the population. 

 No age is exempt, and sex has no apparent influence ; 

 but children are more subject to be attacked than 

 adults, and susceptibility seems to diminish to some 

 extent with advancing age. According to Murchison, 

 only 195 out of 2111 cases received into the Lon- 

 don Fever Hospital, in twenty-three years, were over 

 fifty years of age. To appreciate the value of these 

 figures it would evidently be necessary to know how 

 large a proportion of the exposed population were 

 over fifty years of age. 



Insufficient food 'is generally recognised by medical 

 writers as a potent predisposing cause, and epidemics 

 have so frequently been observed to coincide with 

 periods of unusual scarcity that the name " famine 

 fever " has been applied to the disease. Some authors 

 have even gone so far as to ascribe to starvation and 

 its accompaniments overcrowding and filthy sur- 

 roundings an essential role in the development of 

 the disease. But, as in the case of other specific 

 contagious diseases, there seems to be very little 

 foundation for the idea that relapsing fever may be 

 developed de novo in times of famine, and its epidemic 

 prevalence at such times is to be ascribed rather to 

 increased vulnerability, on the part of the starving 



