CHAPTER V 



RELAPSING FEVER 



D ELAPSING fever is one of the pestilential dis- 

 eases which has contributed considerably to 

 the mortality of Europe, especially during times of 

 famine. It was not clearly recognised as a distinct 

 disease until the eighteenth century, and it is, there- 

 fore, impossible to say to what extent it may have 

 prevailed prior to that time. 



The first clearly recorded epidemic occurred in Ire- 

 land in 1 739, but the literature relating to the disease 

 belongs mostly to the nineteenth century. The fact 

 that the disease was not recognised previously to the 

 date above mentioned cannot be taken as evidence 

 that it did not exist. Typhoid and typhus fevers had 

 not been differentiated as distinct diseases at this 

 time ; and, as all of these diseases are likely to pre- 

 vail simultaneously when insanitary conditions exist, 

 especially in densely populated countries and in times 

 of scarcity of food, it is probable that all of these 



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