134 COMMON RIM'l'ISH ANIMALS 



Rats as Plague Carkiees. 



Many animals, besides rats, are subject to plagnc, 

 and may become plague carriers. Dogs, cats, pigeons, 

 fowls, and many others are known to be victims, but 

 the predominant importance of the rat as a plague 

 carrier is due to his migratory habits and his close 

 association with man, sometimes in vast hordes. He 

 lives in men's houses and warehouses and travels in 

 their ships. 



Both the black and brown rats are susceptible to 

 the disease, but the former is more dangerous since 

 it comes into closer contact with man, living for the 

 most part in ceilings, upper floors and wainscots of 

 houses, while the brown rat inhabits drains, sewers, 

 cellars and stables. 



Recent research has taught us, however, that it is 

 not from the plague-stricken rat itself that man 

 catches the disease, but his blood is inoculated with 

 the germ-laden blood of the plague rat through the 

 bites of fleas, which are parasitic upon the sick 

 animal. Without fleas, plague rats and human 

 plague patients would be harmless except in cases of 

 the pneumonic form of plague. The flea is now 

 know^n to be the all-important agent in causing plague 

 outbreaks. 



For much .of the information I am able to give on 

 this subject I am indebted to the excellent letters 

 written to the ^Times'"^ during the time of the rat 

 plague in East Anglia, 1910) by Dr. Louis Sambon, 



* "The Eat Plagvie in East Anglia/'' ' The Times/ January 30th 

 and February 4th, 1911. 



