202 



PicciNiNNi (F.). Osservazioni epidemiologiche ed anatomo-patologiche 

 nella Peste dei Ratti. Ricerche sperimentali suUa Immunita dei 

 Ratti contro la Peste. [Epidemiological and Anatomopathological 

 Observations on Rat Plague. Experimental Research on the 

 Immunity of Rats against Plague.] — Ann. d'Igiene, Rome, xxx, 

 no. 8, August 1920, pp. 484-496. 



The brown rat, Mus decumanus, represents 90 per cent, of the rat 

 population in and around Naples, and 90 per cent, of the infected rats 

 belonged to that species. The black rat, Mus rattus, and its variety, 

 Mus alexandrinus, are the other species, together with Mus musculus, 

 which latter, however, is of little importance as a plague carrier. 

 Though plague occurs among the rats in the harbour at Naples, most 

 of them are immune. This immunity probably obtains in all the great 

 traffic centres, and is a powerful check that prevents the spread of 

 plague and finally extinguishes it. If rat plague is conveyed from 

 a harbour to the surrounding city, its spread is greatly facilitated 

 owing to the non-immunity, or slowly acquired immunity, of the town 

 rats that inhabit and move about in a very large area, whereas a 

 harbour zone is hmited in extent. This renders more urgent still the 

 necessity for separating a harbour sewage system from that of the 

 surrounding town, as laid down in regulations governing harbour 

 sanitation, thus reducing the opportunities that harbour rats have for 

 entering the town area. The sewer system of the " free harbour " 

 portion of the port of Naples is thus separated, and it is urged that the 

 entire port should be dealt with on these lines. 



Stempell (W.). Ueber den Erreger des Fleckfiebers. [The Causal 

 Agent of Recurrent Fever.] — Sitzungsber. Naturh. Ver. d. preuss. 

 Rheinlande u. Westfalens, 1919 {1917-1919); Bonn, 1920, B, 

 pp. 3-7, 22nd October 1919. 



In reviewing the question of the causal agent of recurrent fever, 

 the conclusion is arrived at that nothing really definite is known 

 except that this organism undergoes several days' development in 

 the louse. It is a fact that epidemics of recurrent fever usually occur 

 in winter and that this disease is not met with in the tropics. The 

 digestive processes in the louse, especially intestinal action, are very 

 dependent on the temperature of its surroundings. Hase has pointed 

 out that at high temperatures an interval of only 2 minutes elapses 

 between ingestion and defecation. It is therefore possible that the 

 slow digestive process entailed by cold weather is necessary to permit 

 the parasites to settle and develop in the gut. This may well be one 

 of the factors responsible for the occurrence of recurrent fever in the 

 cold season. 



Flu (P. C). Onderzoek naar de Levensduur van Stegom.yia fasciata 

 bij lage Temperaturen. [An Investigation of the Length of Life 

 of S. fasciata at low Temperatures.] — Geneesk Tijdschr. Nederl- 

 Indie, Weltevreden, Ix, no. 3, 1920, pp. 418-423. 



These results were obtained in experiments carried out in the cold 

 storage chambers of a steamer. A temperature just beneath freezing 

 point is certain to kill Stegomyia fasciata in 24 hours. In a chamber in 



