205 



The second category comprises parasites that arc apparenth/ peculiar 

 to invertebrates, but these also would appear to be pathogenic to 

 vertebrates in certain circumstances ; in this respect the intestinal 

 flagellates of insects should especially be studied. Investigations 

 do not at present admit of definite conclusions, but it may be that 

 the trypanosomes in the blood of vertebrates will be traced to this 

 origin. Among the parasites exclusive to invertebrates are certain forms 

 (fungi, microsporidia and Hymenoptera) that are definitely harmful 

 to them ; by elucidating their biology it will be possible to use them 

 as valuable auxiliaries in the campaign against such dangerous insects 

 as Glossina. 



The author has collected information from all available sources 

 on the subject of the parasites of blood-sucking organisms. Each 

 of the latter is dealt with under the group to which it belongs. Indices 

 are appended of the invertebrate hosts and of the parasites, and a 

 complete bibliography is also given. 



Chanal (I..). Role pathogene des Moustiques en Pathologie huraaine 

 at comparee. — Lab. Paya$. Fac. Med., Paris, 1921, 91 pp. 



This is a useful compilation of the published data regarding the 

 species of mosquitos that are suspected of being pathogenic, and their 

 relation to disease, particularly to malaria. The synon3miy of each 

 species is recorded, though the author does not claim that it is complete. 

 The disease or diseases transmitted by each species are discussed. 



With regard to malaria, it is recorded whether the species in question 

 has been found naturally infected, and in what proportion, and, wherever 

 possible, any experiments regarding the development of the malarial 

 parasite in it are described. A list of mosquito-borne diseases is given, 

 with the species responsible for their transmission. A useful index 

 is appended, distinguishing the valid species from the synonyms. 



Of 46 species of Anopheles that have been studied for the develop- 

 ment of malarial parasites, complete development of at least one 

 species of human Plasmodium has been shown to be possible in 41 ; 

 in the remainder it did not occur. The degree of receptivity varies 

 with the species ; for example, in the case of P. praccox (falciparum), 

 100 per cent, of A. ludlowi proved infective, ancl only 1-5 per cent, of 

 A. indefinitus. It also varies for the same species of Anopheles accord- 

 ing to the species of Plasmodiitm used ; thus, A . ludlowi became 

 infected with P. praecox 37 times in as many tests ; with P. vivax, 

 38 times out of 47, and with P. malariae, 5 times only out of 107. 

 Recent experiments with large numbers of mosquitos have shown the 

 possibility of infection in some species hitherto not recognised as 

 carriers ; it seems, in fact, as though no species of Anopheline is abso- 

 lutely resistant to development of the malarial parasite, but that in 

 certain species the receptivity is so slight that it is only discoverable 

 after a long series of tests. ' 



It is pointed out that the facility with which the Plasmodiiiin develops 

 in an Anopheline is not the only factor m the epidemiology of malaria ; 

 other points to be considered are the abundance of the mosquito 

 concerned and its biolog^^ The fact that a domestic species that is not 

 easil}^ infected is infinitely more dangerous than a highly susceptible 

 forest species has been largely overlooked, but is of the greatest 

 importance both as elucidating the epidemiology of malaria and also 

 as indicating lines of prophylaxis. 



