Oct., '08] ENTOMOLOGICAL NEWS. 357 



quarters and the district plague sub-stations live fleas have been 

 taken from numerous rats (as many as ninety-seven from a 

 single rat) which had been dead from periods ranging from 

 eighteen to sixty hours. 



The British Indian Plague Commission has demonstrated 

 beyond a doubt the method of rat flea plague transmission. 

 Hundreds of plague rat fleas have been carefully dissected and 

 their internal organs minutely inspected for any evidence of 

 plague bacilli. The salivary glands, the theoretical centre of 

 infection, were, after many painstaking attempts, successfully 

 isolated from the body cavity. These were examined and a 

 plague like organism was found within the secretory ducts. In 

 addition, many fleas were crushed and inoculated into healthy 

 animals. These latter, in every instance where the fleas had been 

 removed from plague rats, succumbed to typical plague lesions. 

 It was taken for granted upon experimental evidence that the 

 transmission was due directly to the co-operation of the salivary 

 glands in the action of the blood-sucking mandibles and 

 epipharynx. 



In a second series of experiments the commission attempted 

 to test further the validity of this theory. Live fleas were re- 

 moved from septicemic Plague Rats and placed in small 

 vials covered with flea net gauze. A flea-clean healthy animal 

 was selected and from a small area on the back the hair was 

 shaved. The mouth of the vial was then placed against the 

 smooth skin and the flea permitted to bite through the gauze, 

 After biting, the insect was immediately withdrawn and the 

 animal placed in a flea-proof cage and observed. A similar 

 animal was taken and treated in an identical manner, but im- 

 mediately on withdrawing the flea, after it had bitten, a plati- 

 num needle loopful of a plague flea's intestinal evacuation was 

 rubbed into the bite. These experiments were duplicated and 

 the results showed a marked uniformity. In no instance did 

 the flea bite alone prove fatal, but in a large percentage the 

 bites which were accompanied by the inoculation of the intes- 

 tinal discharges caused a rapid death with post mortem plague 

 positive verifications. It appears, then, that the disease trans- 



