39 



With regard to the readiness with which Ceratophyllus 

 fasciatus, the common rat flea in Europe, attacks man, 

 considerable divergence of opinion has hitherto existed. 

 According to Wagner (quoted by Tiraboschi 1904, p. 180), 

 Tiraboschi (1904, p. 266), and Galli-Valerio (1907), this flea 

 does not bite man. On the other hand, Gauthier and 

 Raybaud (1903 and 1909), and McCoy and Mitzmain (1909) 

 found that when hungry it fed on man with readiness. 



Dr. Harriette Chick and I (1911) have made some hundreds 

 of experiments on this question, and are at a loss to under- 

 stand the negative conclusions arrived at by Tiraboschi and 

 Galli-Valerio. Under the conditions of our experiments 

 Ceratophyllus fasciatus fed upon man as readily as upon a 

 rat. (Table III.) Nevertheless, it is doubtful whether 



TABLE III. Showing llesults of Feeding Experiments with 

 Ceratophyllus Fasciatus. 



Ceratophyllus fasciatus is attracted to man as readily as is 

 X. cheopis. Compared with the latter, it is a poor jumper. 



We also made 107 experiments with Ctenopthalmus agyrtes, 

 a flea common on Mus deoumanus in this country, when 

 living in fields, ricks, or barns, and 122 experiments with the 

 mouse-flea Ctenopsylla musculi. Under the conditions of the 

 experiment the former would not bite man at all, and the 

 latter only very occasionally. This latter experiment is 

 interesting, because mice, although dying from plague, have 

 not been found to be associated in the same way as rats 

 with the origin of plague epidemics. 



