160 



The curve of rat plague preceding that of human plague in Bombay 

 has been obtained by comparing the number of dead rats found with 

 the number of rats caught in traps, etc., these being figures that are 

 dependent upon different factors. If, however, the percentage of 

 plague rats among the total caught is marked in the curve, the lines 

 of rat plague and human plague show a striking parallelism, suggesting 

 that the disease in both species may be brought about by the same 

 factor. This factor is the rat-flea, transferred over long distances 

 by goods and in the vicinity by its own mobility. In the flea the 

 plague virus may remain active for a long time, and this is not possible 

 either in man or rats. This persistence in the flea may account for 

 the seasonal recurrence of plague epidemics in Bombay and, formerly, 

 in Europe. 



The connection between rat plague and human plague in Europe 

 has remained uncertain in recent epidemics. On the other hand, the 

 probable transfer of human plague by persons watching the corpses 

 of plague, victims has been observed, fleas being very common in the 

 class affected. In natives of the tropics, with their scanty clothing 

 and greater bodily cleanliness, human fleas are rare. It is considered 

 that views on the mode of spread of plague in Europe have been, 

 too largely influenced by experience in the tropics. 



Reichenow (E.). Intracellulare Symbionten bei blutsaugenden Milben 

 und Egeln. [The Intracellular Symbionts of Blood-sucking Mites 

 and Leeches.] — Arch. f. Protistenk., Jena, xlv, no. 1, 29th April 

 1922, pp. 95-116, 8 figs. 



The intracellular fungi of mites and leeches are described. In the 

 author's opinion these may have some effect on the blood of the 

 vertebrate on which their host has fed. 



KuHN (P.). Untersuchungen iiber die Fliegenplage in Deutschland. 



[Investigations on the Fly Pest in Germany.] — Centralhl. Baki., 

 Paras., Infektionskr., Jena, Ite Abt., Orig., Ixxxviii, no. 3, 

 22nd May 1922, pp. 186-204. 



A thorough investigation of the occurrence indoors of Miisca 

 domestica, L., and Stomoxys calcitrans, L., undertaken in Alsace and 

 Baden, is described. 



From June 1915 to May 1917, 532 dweUing-rooms and stables were 

 provided with fly-papers ; the number of these was 49,426, and 

 they captured 4,359,658 M. domestica and 282,202 5. calcitrans. 



M. domestica is about as numerous in dwellings as in pig-sties. In 

 the aggregate, stables and cow-sheds each contained twice as many 

 M. domestica as dwellings. In Strasburg, M. domestica was more 

 abundant in cow-sheds than in stables, but elsewhere the opposite 

 was the case. The figures outside Strasburg indicate that M. domestica 

 is chiefly found in stables. The relatively lower figures for this town 

 probably depend on the more thorough removal of horse manure 

 as compared with elsewhere. 



S. calcitrans prefers cow-sheds. According to Wilhelmi, its eggs are 

 mainly laid in cow-dung. It may also, hke mosquitos, prefer the 

 blood of cattle. It occurs in dwelhngs within a radius of about 

 200 yards of sheds or places where cattle occur. 



The data obtained from the fly-papers indicate that M. domestica 

 nearly always predominates over 5. calcitrans in dweflings, the season 

 being immaterial. 



