1910] RucJcer, California Ground Squirrel and Bubonic Plague. 141 



.March, the average litter containing seven or eight. Litters as 

 large as eleven have been found. On account of the great fond- 

 ness of the gopher-snake, the red winged hawk, the coyote and the 

 red fox for the young ground squirrels, they usually spend the 

 first month or six weeks in the hole, under the guardianship of the 

 wary old females. As soon as they have become able to look after 

 themselves, the migration into the lower lands begins. By this 

 time the rainy season has closed, the ground has become fairly 

 dry, the barley is reaching maturity, and before long the cherries, 

 peaches, pears and prunes begin to suffer from their depredations. 



Two species of fleas are commonly found upon ground squir- 

 rels — the Ceratophyllus fasciatus in greatest abundance, and the 

 Hoplopsyllus anomalus more rarely. Recent experiments have 

 definitely proven that these fleas will transmit plague not only 

 from squirrel to squirrel, but also from squirrel to rat and from 

 rat to rat. It is therefore very easy to see how in the suburbs of the 

 city, where the life zones of the rat and the ground squirrel overlap 

 one another, an interchange of fleas may take place, and if these 

 fleas leave a plague-infected ground squirrel, finding lodgment 

 upon a well rat, that animal may thus receive the disease and be- 

 come the starting point of an epizootic among city rats and an 

 epidemic among human beings. 



Here then we have an explanation of the way in which plague 

 entered San Francisco the second time. It is not altogether im- 

 probable, however, that until very recently a second factor had to 

 be dealt with. As is well known, the ground squirrel has been 

 considered a delicacy and has been eaten in large numbers by the 

 people of California. In fact, there are numerous poor families 

 who have no other kind of meat. The danger in this regard is 

 twofold. One aspect of this question may be best illustrated by 

 the following case : 



On July 17th, 1900, hunter employed in the work of plague 

 scouting, shot near the Fish ranch, a few miles out of Berkeley, in- 

 fected ground squirrels. On the 21st of October following, a 

 young butcher named Frank Bonfils, in spite of the warnings 

 which had been issued broadcast by means of posters, circulars 

 and notices in the public print, shot twelve ground squirrels in the 

 same locality. On October 23rd he was stricken with bubonic 

 plague. 



