8^ 



in vivo can be employed to reveal the presence of malarial parasites 

 when existing in small numbers in the peripheral blood. A Javanese 

 coolie, the carrier of numerous crescents, was bitten by many individuals 

 of Anopheles {Myzomyia) ludlowi, all of which became infected, and 

 two of them subsequently transmitted mahgnant tertian malaria 

 (Plasmodium fraecox) to two previously healthy persons. Of 15 

 individuals of A. hyrcanus {M. sinensis) and 68 of A. (M.) umbrosus, 

 two of each species also became infected, although both species 

 generally prove immune to P. praecox {falciparum). The pigment of 

 the young oocysts in A. hyrcanus and A. utnbrosus was found to be 

 fine and of a yellowish brown colour, contrasting with the thick, black 

 pigment of the oocysts of malignant tertian malaria found in A. ludlowi, 

 and accompanied by less numerous oocysts with fine pigment. The 

 fine, yellowish-brown pigment seems to be characteristic of the 

 oocysts of P. vivax, especially when young. The coolie in question 

 therefore undoubtedly suffered from a mixed infection of malignant 

 and benign tertian, the latter being revealed only after several days' 

 repeated microscopic examination of the peripheral blood. From 

 another coolie, suffering apparently from a pure infection of P. praecox, 

 a mixed infection of P. praecox and P. vivax has been recovered from 

 the Anopheline vectors, and the latter parasite has also been 

 transmitted to a healthy individual who contracted benign tertian 

 malaria. 



It is therefore sufficient to induce biting by a mosquito the stomach 

 of which is examined after four days or more ; if oocysts are discovered, 

 the nature of the pigment is sufficient to determine the species of 

 parasite. The parasite of quartan malaria is the only one that 

 presents difficulties in determination, the pigment being intermediate 

 in character between that of P. vivax and P. praecox. 



The explanation of A. ludlowi not transmitting benign tertian in 

 the first case recorded hes in the fact that in the blood ingested P. vivax 

 was very scarce and crescents were very numerous, with the result that 

 the oocysts of P. vivax were overwhelmed by those of P. praecox and 

 remained in an immature state. In the case of P. praecox in the 

 stomach of A. hyrcanus the surrounding medium was evidently not 

 favourable to developm^ent, and therefore the few gametes of P. vivax 

 ingested at the same time were able to develop. 



M. Brumpt in commenting upon this paper remarks that he has 

 made use of the method for many years in his studies of trypanosomes. 

 M. Roubaud considers that the practice, while interesting, cannot 

 be relied upon for absolute accuracy, chiefly because Anophelines 

 do not always become infected from gamete carriers, and the same 

 uncertainty is still more marked in the case of the development of 

 pathogenic trypanosomes in Glossina. 



Delanoe (P.). Un Cas d'Infection spontan^e du Chien par 

 T. marocanum, Sergent, Lh6ritier et Belleval, 1915.— Bull. Soc. 

 Path. ExoL, Paris, xiii, no. 1, 14th January 1920, pp. 23-26. 



The case is recorded of a dog observed in Morocco, in August 1919, 

 to be suffering from trypanosomiasis caused by Trypanosoma 

 marocanum. 



