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woman (M. P.) died July 28, on a ranch 10 miles from Martinez. 

 The two were not associated. An investigation was ordered at once 

 and a force of trappers was hurried to the scene with instructions to 

 collect squirrels from the ranches in the vicinity. The first plague- 

 infected squirrel was found August 5 on the ranch where the boy had 

 died July 15. Of 425 squirrels collected from August 1 to October 

 12, 4 showed the gross and microscopic lesions of natural plague. 

 A lad (F. M.) sickened August 5, 1908, in Los Angeles, Cal., after 

 being bitten by a sick ground squirrel. A polyadenitis, which after- 

 wards proved to be plague, developed in a few days. A dead squirrel 

 was found nearby and pathological specimens taken from it were sent 

 to the United States Plague Laboratory in San Francisco. McCoy 

 recovered B. pestis from the tissue of the animal. This was the 

 only case of plague reported in Los Angeles. In order to complete 

 the list of those who contracted plague in the country, two other cases 

 shoidd be mentioned. F. S., a pregnant woman, died of bubo- 

 septicsemic plague near Concord, Cal., February 29, 1904. The 

 B. pestis was recovered in pure culture from the axillary glands. In 

 April, 1906, a school boy of east Oakland developed a multiple plague 

 adenitis. Investigation showed that he had shot and handled ground 

 squirrels in the country four or five days before his illness. 



THE NATURAL HABITAT OF PLAGUE. 



The location of the natural habitat of plague has concerned sani- 

 tarians for many years: Not a few have settled upon India as the 

 endemic center, while others associate China with the epidemics 

 which have devastated Europe from remote times. Le Dantec, a 

 recent writer, suggests the "lofty mountains" between India, Thibet, 

 and China as the exact location, and selects the rodent (marmot) of 

 that region as the natural enzootic host. 



A panzootic leaves in its wake .enzootics of plague in various coun- 

 tries which persist until the rodents upon which they thrive are either 

 exterminated or rendered immune. At varying intervals epidemics 

 spring from them and finally cease with the exhaustion or destruction 

 of the enzootic foci. Plague disappears inwtime from these temporary 

 abodes and retires to its original habitat in India or China. 



Of serious import in this connection is the fact that all the condi- 

 tions necessary for the establishment of a permanent focus of plague 

 exist on the Pacific coast of the United States. The broad valleys 

 and lofty mountains of this region are rich in the ardomyinse, there 

 being no less than 12 species in California alone. In the high Sierras 

 the marmot {Marmota jlaviventer) ,'^ a species of the natural enzootic 

 host of Le Dantec, is found in great numbers. The ground squirrel 

 infests the valleys and foothills in an unbroken chain from Ore- 



o " California Mammals," Frank Stephens. 



