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rats; its stated hosts are, according to Thompson, Mus albipes of Socotra 

 and Herpestes ichneumon of Egj-pt. This species, the author states, bit 

 human beings in laboratory trials, as did also Pulex fasciatus on one 

 occasion. Typhlopsylla miisculi did not bite.^ 



Thompson, who, during the Sydney epidemic, observed blebs which he 

 considered to be produced by fleas and to be the place of entrance of 

 the plague virus, concludes that the transmission of plague from rats 

 and mice through the intermediation of fleas must be frequent. 



Zirolia believes that plague can easily be spread by fleas. He observed 

 Pulex irritans and P. serraUceps, after they had been fasting for some 

 time, to suck blood from a plague-infected mouse, and he found living, 

 virulent plague bacilli in the bodies of these fleas seven to eight days 

 thereafter. Zirolia also says that the feces of fleas from plague-infected 

 animals contain virulent bacilli, and that in the bodies of the dead 

 fleas these parasites survive for a long time. 



Maxwell, from his observations made at Changpoo, China, states that 

 he is coming more and more to doubt the rat-flea theory. "I can not 

 see," he says, "how we can escape plague. I must have been bitten, 

 in spite of flea powder, many times off plague patients and so must 

 my students. The Chinese, especially the women, catch the fleas and 

 kill them with their teeth. If they catch fleas with plague bacilli in 

 them, how do they escape?" 



The Indian Plague Commission, which studied plague in all of its 

 phases in India, has also looked into the question of insects as carriers 

 of the disease, and in its report states that Simond's endeavors to 

 establish the proposHion that suctorial insects play an important part 

 in the transfer of plague from sick to healthy animals is so weak as 

 hardly to deserve consideration. The experience of plague hospitals in 

 India, and especially that of the Arthur Road Hospital at Bombay, seems 

 to indicate very clearly that suctorial insects do not come into consideration 

 in connection with the spread of plague. The staff and attendants in 

 the Arthur Road Hospital (where thousands of plague cases are treated) 

 were continually bitten by insects, especially mosquitoes, and yet no cases 

 of transfer of the infection from the sick to the healthy came under 

 observation. 



The commission also states on reviewing all the facts which have come 

 to its knowledge, that it has little reason to suppose that ordinary, casual 

 contact with plague-infected rats, dead or alive, is especially liable to 

 convey the disease. On the other hand, examples are known of cases 

 where the bite of plague-infected rats and other animals has conveyed 

 the disease. 



^ Galli-Valerio, trying to invalidate Tidswell's observations, says that 

 this author, like others, failed to transmit plague from rat to rat through 

 the agency of fleas and proposes the question: "If the transmission is so 

 difficult from rat to rat, why, on the other hand, should it be so frequent 

 from rats and mice to man, who is not as a general rule attacked by 

 mouse and rat fleas?" 



