148 INSECTS AND MAN 



of their being so. Verruga exists to-day in certain valleys 

 on the Pacific slope of the Peruvian Andes; its origin is 

 a mystery, but it is no new-comer, for, at the time of the 

 Spanish conquest, it was more widespread than at present ; 

 in fact, certain reliable authorities maintain that the 

 disease has existed in the quebradas of the Rimac from 

 the most remote times. When the Spaniards came to Peru, 

 verruga extended from South Central Peru to Northern 

 Ecuador. Four centuries ago, the armies of Huayna Capac 

 were decimated by a disease, probably verruga; for 

 small-pox, which, by some, is considered to be a more 

 likely disease to decimate an army, was unknown at the 

 time in these regions, having been introduced by the 

 Spaniards at a later date. 



As we shall see later, the disease exists in two stages 



or phases, a fever phase and an eruptive phase, and at 



least nine different names have been applied to each of 



these two stages. No purpose would be served by giving 



a complete synonymy, but special interest attaches to the 



names Carrion's grave fever and mule warts for the fever 



and eruptive phases respectively. Localities where the 



disease may be contracted are invariably situated in or 



near deep narrow canyons with luxuriant vegetation and 



great summer heat, combined with little ventilation. Dr 



Ernesto Odriozola, senior member of the Lima Faculty of 



Medicine, who has made a special study of verruga, says 



that all ages and races of men are susceptible, as well as 



certain domestic animals. The fact that mules often 



exhibit eruptions similar to those found on human patients 



has given rise to the name mule warts for the eruptive 



phase of the disease. All degrees of intensity may be 



exhibited, the most serious form being called Carrion's 



grave fever, on account of the fact that, in the 'eighties, 



an investigator named Carrion " vaccinated " himself with 



blood from a verruga tumour, thereby proving, at the cost 



of his life, that transmission by inoculation is possible. 



