51 



fleas. Exj)eriments have shown that parasitisation reaches its height 

 in the month of May, which is also the month in which the epidemic 

 was at a maximum in 1916, when these investigations were made. 

 This is the driest period of the year ; with the coming of the rains, 

 the number of flies decreases and plague gradually subsides. The 

 importance of the role of XenojjsijUa {Pulex) cJieojns in the transmission 

 of plague from rat to man has already been proved. The degree of 

 parasitisation of the domestic rat was found to be low but remarkably 

 constant ; in the case of the sewer rat, parasitisation is highly 

 developed, and, as this species is liable to plague infection, its presence 

 constitutes a great danger. The musk-rat also is a carrier to be 

 reckoned with [see this Review, Ser. B, iii, p. 97]. 



About 95 per cent, of the parasites taken from rats proved to be 

 X. cheopis ; Pulex iniians is not specially common, but (Jtenocephalus -^ , 

 (P.) canis is found sometimes in swarms in sandy places owing to the Y 

 abundance of stray dogs. Cats have been observed covered with fleas '^ 



of an undetermined species. In the case of X. cheopis, eggs do not 

 hatch under 55° F., and at 90° F., 75 per cent, remain sterile ; on the 

 other hand, a dry atmosphere seems to have no influence on their 

 fecundity. For the active larvae a certain amount of moisture and a 

 still atmosphere are necessary ; badly ventilated houses therefore 

 favour their occurrence. During the pupal period the insect offers 

 great resistance and can survive 12 hours of complete immersion. 

 The adult can live 38 days without food and lives for preference on the 

 body of its host rather than in its bed, which makes it a far more 

 dangerous agent in plague transmission. The temperature of South 

 Annam is very uniform and is never hot enough to offer a serious 

 obstacle to hatching, while the conditions under which the natives live 

 offer every encouragement to the increase of the pests. The two great 

 reforms necessary are the extermination of rats from dwelling-places 

 and other centres of attraction, and the amelioration of housing con- 

 ditions, which, in the present state of squalor and ignorance among 

 the populace, are not easy to accomplish. A code of remedial 

 measures against plague epidemics has however been formulated in a 

 decree issued by the Governor-General, acting on the advice of the 

 medical inspector. 



PiOT (J B.). Maladie des Tiques. Traitement pr6ventif et curatif pour 

 I'Egypte. [Tick Disease. Preventive and Curative Treatment 

 for Egypt.] — Bull. Union Agriculteurs d^Egypte, Cairo, xiv, 

 no. 117, November-December 1916, pp. 85-88. [Received 

 17th February 1917.] 



Cattle in Egypt, if left untended, frequently become entirely covered 

 with ticks. It has been proved "that infection in the tick is hereditary 

 and that the piroplasm occurs in the salivary glands of the larvae, 

 which can therefore directly inoculate the host. Piroplasmosis in 

 cattle may be acute or chronic, the acute form being often responsible 

 for a mortahty as high as 80 per cent. The only curative treatment 

 which the author has found to give complete satisfaction, other than 

 quinine and trypanblue, is arrhenal ; a hypodermic injection of one 

 dose of one gramme is generally sufficient to allay the fever. This 

 treatment to be effectual must be given as soon as the symptoms of the 



(C360) a2 



