297 
THE REGIONAL DISTRIBUTION OF FLEAS 
ON RODENTS. 
By GEORGE W. McCOY, 
Passed Assistant Surgeon, 
United States Public Health and Marine Hospital Service, 
and MAURICE B. MITZMAIN, B.Sc., 
Assistant, Plague Laboratory, United States Public Health and Marine 
Hospital Service, San Francisco, California, U.S.A. 
This investigation was prompted by the fact that in the study of the 
lesions of natural plague infection among rats in San Francisco it was 
found that the anatomical changes produced by the disease were practic¬ 
ally identical with those described by the British Plague Commission 1 in 
India, except that in San Francisco the location of the bubo in the great 
majority of cases was in the inguinal region, and practically none of the 
buboes were found in the cervical region. In India, however, the great 
majority of the buboes, 74\3°/ 0 in 2956 rats, were located in the cervical 
region, a comparatively small percentage, 14*S°/ 0 , were in the inguinal 
region and 10‘9°/o in the axilla. These figures refer to single buboes 
only. It was assumed that fleas were responsible for the epizootic 
among the rats here, as had been shown to be the case in India. 
Wherry, Walker and Howell 2 , in a paper on rat plague, as observed 
in San Francisco, state that the buboes they observed were distributed 
as follows : one in the cervical region, one in the axilla, and six in the 
inguinal region. One of the present writers 3 reported that in San 
Francisco, among 29 rats showing single buboes, no case of cervical bubo 
1 Journal of Hygiene, Vol. vii. No. 3, p. 386. 
2 Journal American Medical Association, April 11, 1908, Vol. l. No. 15. 
3 Public Health Reports, Washington, Vol. xxxm. No. 30, p. 1051. 
