298 
Fleas on Rodents 
had come under observation, while in 21 cases (72 - 4°/o) the lesion was in 
the groin, in six cases (20’4°/o) in the axilla and twice (6'9°/ 0 ) in the 
location of the pelvic glands. In the later experience in San Francisco 
no case of cervical bubo has been observed. 
The Indian Plague Commission 1 found that the situation of the 
buboes in nearly 200 guinea-pigs experimentally infected with plague 
by fleas was as follows: 88‘9°/ 0 were found in the neck, 9'3% in the groin 
and l'8°/o in the axilla. These figures are given for those animals having 
single buboes, constituting 90'5°/ 0 of all. The remainder had multiple 
buboes, i.e. in two or more situations, and in these animals the neck 
glands were affected in every instance. An effort was made by these 
observers to ascertain the connection between the situation of plague 
buboes and the distribution of the fleas on the body of the animal. It 
had been noted as a common observation that the favourite situation of 
fleas on the body of animals was the under surface of the neck and be¬ 
neath the chin, i.e. in the cervical region. An actual count was made on 
the bodies of 53 live guinea-pigs which were placed singly in a wide¬ 
mouthed, stoppered bottle containing a piece of wool soaked in chloro¬ 
form, thus stupefying both the animal and the fleas at the same time. 
The fleas were removed and a careful record taken of the situation in 
which they were found. A census of the anaesthetized parasites showed 
65'3°/ 0 taken on the head and neck, 11 ’5°/ 0 on the forelegs and axillae, 
12'9°/o on hind legs and groin, and 10’2°/ 0 on the trunk of the animal. 
The commonest situation in which fleas occur on guinea-pigs was thus 
demonstrated to be the head and neck, the region drained by the cervical 
lymph glands. In these experiments and observations the species of flea 
concerned was that common to the rats of India, Loemopsylla cheopis, 
Rothschild. 
The only definite statement we have encountered on the subject of 
the regional distribution of fleas on rats is that of Pound 2 , who, in 
speaking of the distribution of fleas on their host, says, “ Thus with 
regard to rats, fleas more commonly occur, when infesting these rodents, 
about the head and neck than elsewhere.” 
The Indian Plague Commission makes no statement, so far as we 
have been able to determine, as to the regional distribution of fleas on 
rats, but the fact that they found the majority of the buboes in the 
cervical region leads one to draw the inference that this is the region 
most infested by fleas in India. As cited above, they demonstrated by 
1 Journal of Hygiene, Vol. vi. No. 4, p. 465. 
2 Report on Plague in Queensland, 1900-1907, p. 143, B. Burnett Ham. 
