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PLAGUE, RATS AND FLEAS. 



By Capt. W. G. Liston, i.m.s. 



(With Plates A. & B.) 



{Read before the Bombay Natural History Society 



on 2ith November 1904.) 



You may, perhaps, think that the choice of such a title for a paper to 

 be read before a Natural History Society is somewhat out of place, and 

 would have been more suitable for a medical gathering. Perhaps you 

 are right, but I feel sure that the subject has a proper place under the 

 circumstances. We are daily becoming more aware of the important 

 part played in the spread of disease by the numerous animals and 

 insects which surround us, and, as you will learn in the course of my 

 remarks, plague is a disease which is pre-eminently dependent on such 

 surroundings. A knowledge of Natural History is becoming a more 

 important, I may say an all-important, branch of the medical pro- 

 fession. Quite apart, however, from such facts, plague is in the midst 

 of us, carrying on its deadly ravages, and adding daily to its already 

 uncountable death roll hundreds who, through ignorance of its mode 

 of spread, fall victims to the scourge. Any ray of light shed into the 

 darkness which surrounds the aetiology of this disease should not be 

 confined to the medical world, but be cast upon the people that they 

 may, perhaps, be enabled thereby to grope their way through the dark- 

 ness to a place of safety. 



You will appreciate the relation between Natural History and 

 plague when I define the latter as a rat-disease. Not unfrequently, 

 under favouring circumstances, it is communicable to man. The disease 

 among men, therefore, might almost be said to be accidental, and cer- 

 tainly avoidable if there were a distance between rats and men. The 

 communication of the disease to man is conditional on the propinquity or 

 distance of rats and men from one another, and is dependent partly on 

 the habits of the former and partly on the modes of living of the latter. 



The ideas embodied in the above definition are not new. That 

 plague is essentially a rat-disease was known to the ancients. 

 We find the disease attributed to these animals by the priests 

 and diviners of the Philistines, who instructed the people in these 

 words — "Make images of your emerods and images of your mice that 

 mar the land." They were to do so as a trespass offering to the God 

 of Israel. (*) In the Bagavathi Purana the people are advised at th© 



