77 



However, the report of the commission does contain some information 

 which suggests that pediculi may be factors in the spread of plague. 

 According to the Bombay statistics of the plague epidemic of 1896, the 

 rate of mortality per 1,000 individuals among the Jains ^ of that city 

 as compared with that among other castes is surprisingly large,' and it 

 is believed to be due to the fact that animal life is sacred among the 

 Jains. "They will not." the report states, "sweep their staircases, or 

 sweep their sleeping rooms, or their cooking rooms very often, lest they 

 should destroy some animal life, so scrupulous are they. * * * Xot 

 that their places are very dirty. They are a wealthy people, and their 

 places look comparatively clean. * * * The Jains, owing to their 

 aversion to taking life, are said to be infected with parasites." 



A NEW SPECIES OF RAT FLEA. 



As yet much evidence certainly has not been presented in favor 

 of the theory that the most important intermediaries in the spread- 

 ing of plague from rats to man are fleas from plague-infected 

 rats. Even if rat fleas should have played an important role in 

 the spread of plague in Sydney, as maintained by Tidswell and 

 Thompson, their conclusions can not be generalized. How neces- 

 sary it is to study this question in every place where plague occurs 

 endemically or epidemically is shown by our observations of the 

 rat fleas in Manila. Looking into this subject, we found, somewhat 

 to our surprise, that the fleas infesting rats are not identical with 

 those which have been described for other countries. Indeed, the 

 species found here on rats appears to be new. Previous to the 

 time when the writer began to collect rat fleas. Dr. W. B. Wherry, 

 bacteriologist of this Laborator}^ had already collected eight, which 

 he kindly placed at my disposal. Thirty-four were subsequently 

 caught. It is not easy to procure a large number of rat fleas, 

 because, when the rodents have been caught, by the time they are 

 killed and examined, the fleas have left them. For this reason 

 Dr. Wherry succeeded in obtaining only eight fleas from flfty- 

 three rats; while the thirty- four others were subsequently obtained 

 from about one hundred animals. A few of the parasites were 

 procured alive, were kept in a glass vessel for some time, and were 

 then given an opportunity to bite both Caucasians and native 

 Filipinos. In not a single instance did any of these fleas bite 

 human beings. We have also collected a number of fleas from 



^Average mortality per 1,000 males in the plague epidemic of 1896 at 

 Bombay, 2.63; per 1,000 females, 1.88; per 1,000 male Jains 8.69; per 

 1,000 female Jains, 6.77. 



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