142 Bulletin Wisconsin Natural History Society. [Vol. 8. No. 3. 



Now, in this case the fleas happened to attack the hunter, but 

 it is quite conceivable that the fleas, leaving the carcass of the 

 squirrels after he carried them into Berkeley, might have found 

 lodgment upon rats, thus relighting the epizootic among a species 

 which comes in daily contact with man, in whom an epidemic 

 would be launched. 



It would seem as though plague among ground squirrels might 

 be a providential thing. These animals are a continual economic 

 menace to the rancher, and anv disease which would reduce their 

 numbers would, be welcomed. Unfortunately, (and this is the 

 all-important point) this species rapidly acquires a certain degree 

 of immunity to plague, and we received specimens showing healed 

 or chronic lesions of the disease. The animal living would perpet- 

 uate the pest among his species. We might, then, liken the ground 

 squirrel to a reservoir for the holding of the infection, with the 

 rats as a connecting channel between this reservoir and man. 



It is found in India that the animal which keeps the disease 

 alive is very similar to our ground squirrel. It is called by various 

 names, the tarbagan, the marmot and the Arctomys bobac. In 

 West Africa a wood rat somewhat similar to our Netopia fuscipes 

 is supposed to keep the disease alive, and in the third great focus 

 on the western coast of the United States, it is the Citellus Beechyi 

 which perpetuates this Oriental monster of pestilence. 



The solution of this problem is an Herculean task. Plague is 

 a hydra-headed monster, sinuously entwining itself about the in- 

 tricacies of human life. In order to eradicate plague forever from 

 the United States, it is necessary that the Citellus Beechyi in the 

 infected zone be entirely exterminated. Secondly, that the rodent 

 population of the entire nation be made a subject of careful in- 

 quiry, to discover if perchance the seeds of pest have been dropped 

 in a soil hitherto unsuspected ; and, having assured ourselves that 

 we are free of the disease, our quarantines should take cognizance 

 of the rat rather than the human passenger as the vehicle for the 

 transportation of the germs of the scourge. 



It has been estimated, and I consider it very conservative, that 

 it costs $i.oo per annum for the sustenance of a single ground 

 squirrel. I myself have seen entire vineyards despoiled by the ma- 

 rauding bands. A beautiful almond orchard in the San Ramon 

 Valley has been abandoned because of their depredations, and in 



