IN-TEODUCTION. 



15 



The last great outbreak of pneumonic plague in Manchuria, during 

 the winter of 1910-11, was supposed to have started among tar- 

 bagan hunters in the to-vvn of ManchouH, a station on the Trans- 

 Siberian Railway, whence it spread rapidly southward along the rail- 

 way to Harbin and Mukden. Efforts were made during the progress 

 of this epidemic to locate the disease among the native marmots/ 

 and a number of individuals captured near Mukden were inoculated 

 experimentally by Prof. Zabolotny and found susceptible to plague 

 infection. One individual suffering from the disease was brought to 

 him, this being the only knoT\ni instance of the natural appearance of 

 plague among marmots. ^ More recently a systematic effort has been 

 made by the Chinese Government to discover the disease in nature, 

 but the evidence obtained is wholly of a negative character.^ 



The experimental evidence just mentioned and the close relation- 

 ship of marmots to ground squirrels, which are known to carry plague 

 on the Pacific coast of North America, warrant looking upon these 

 animals with suspicion whenever they occur in a plague-infested region. 



One American species — the golden-mantled marmot (Marmotaflavi- 

 ventris nosopJiora) — is known to assist in spreading the deadly spotted 

 fever by serving as host for the fever tick (Dermacentor venustus) , both 

 in adult and nymphal stages. Over 200 ticks have been taken from a 

 single wild marmot, and when in captivity the species has been shown 

 to be susceptible to spotted fever.^ Since this marmot is not utihzed 

 for fur there is relatively little danger of the spread of the disease to 

 other regions through the medium of the animals, but every effort 

 should be made to exterminate them where they occur about culti- 

 vated lands or in the vicinity of dwelhngs. Suggestions for destroy- 

 ing marmots are given in Farmers' Bulletin 484, United States De- 

 partment of Agriculture. 



EXTEENAL CHAEACTERS. 



In the American marmots the body is thickset and clumsy; the 

 head short and broad; the legs short and stout; and the tail rather 

 short (about one-fifth to one-third of the total length), densely haired, 

 and slightly flattened. The nose is broad and blunt, covered with 

 hair to the edge of the nostrils, and the ears are short, broad, rounded, 

 and well-haired. Tufts of long black bristles grow from the side of 

 the head, one directly behind the nose, another underneath and 

 between the eye and ear, and a third shorter tuft over the eye; small 

 scattered bristles also are found under the chin. The eyes are rather 



1 The marmot of Manciiiiria, although generally referred to in plague literature as Arctomys hohac, is in 

 all probability Marmota sibirica, specimens of which, collected at Urga, Mongolia, are in the U, S, Na- 

 tional Museum. 



2 Strong, R. P. Rept. Intern. Plague Conference held at Mukden, April, 1911. Manila, 1912^ 



3 Dr. Wu Lien Teh (G. L. Tuck). The Lancet, London, Aug. 23, 1913, pp. 529-535. 

 < Birdseye, Clarence. Farmers' Bui. 484, U. S. Dept. Agr., 1912, p. 28. 



