254 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XVI. 



moment rats fall from the roof above, jump about, and die to leave their 

 homes with their friends and relations, and to live in the plain. ( 2 ) In 

 Knmaun, where the disease has been known for long, the experience of 

 the inhabitants has taught them that when rats die it is time to quit 

 their homes for the jungle to save themselves from plague. It is stated 

 in a report of the outbreak of 1834-35 that " the appearance of the 

 disease in a village had been observed to be preceded by a mortality 

 among the rats of the village." ( 3 ) Coming to more recent times, 

 Hankin, in reviewing the various circumstances that produced plague 

 in Bombay, inferred that the incidence of Plague in localities and houses 

 was in relation to their accessibilty to rats rather than to filth, over- 

 crowding, &c. ( 4 ) Simond also came to a similar conclusion from his 

 experience of the disease. ( 5 ) 



Dr. Ashburton Thompson, from his experience of the outbreak of 

 plague in Sydney in 1900, formed the opinion that plague-rats consti- 

 tuted the sole source from which the infection was communicated to 

 man. ( 6 ) Dr. G. J. Blackmore, formerly Chief Plague Medical Officer, 

 Port Elizabeth, very clearly and conclusively proved that the epidemic 

 in that town was altogether spread by rats. He writes : " To sum up 

 shortly, in places where infected rats were found, plague cases followed ; 

 and in places where there were no infected rats, only four cases of 

 plague occurred, and in these cases the source of infection could not be 

 traced at all. In no case was there direct evidence of man-to-man 

 infection, and in most cases the possibility of it was definitely exclud- 

 ed." (J) I need not quote further in this connection. It is absolutely 

 certain that rats are the most important factor in the spread of plague. 

 If plague is a disease of rats, then it is likely that the disease may have 

 its own distinct laws of origination and continuance among these 

 animals, man becoming affected chiefly when the disease is most pre- 

 valent among rats. It is precisely this study of plague among rats 

 that has been neglected. Before any progress in this connection can 

 be made, it is necessary to know something about the life and habits 

 of rats. 



What do we really know about rats ? Very little. Now this is one 

 reason why I am reading this paper before you to-day. You are all 

 naturalists and, no doubt, keen observers. May I ask you to direct 

 your attention to rats ? Any notes upon the habits of these animals 

 will be thankfully received by me. 



