HiEMOSPORIDIA 87 



and referred also to the analogy of the trypanosomiasis of cattle which is 

 transmitted by the tsetse-fly; nevertheless, Koch likewise could furnish na 

 proof. 



Ross (21), inspired by Manson, first succeeded in following the develop- 

 ment of the plasmodia that had reached the stomach of the mosquito 

 with the blood of malarial patients, especially after he had made Proteo- 

 soma (Hcemoproteus} living in birds the subject of his investigations. He 

 found that the proteosoma in the stomach of the mosquito penetrate into 

 the intestinal wall, grow into large cysts and produce innumerable rod- 

 shaped spores, which are set free in the body cavity of the mosquito by 

 the bursting of the cysts, and then make their -way into the salivary 

 glands. When Ross allowed mosquitoes to suck the blood of infected 

 birds, and about nine days later fed on healthy birds the infected mosquito 

 that had been kept isolated, proteosoma were discernible in the blood of the 

 birds five to nine days later. 



These researches confirmed the mosquito-malaria theory, at all events 

 as regards the malaria of birds, and its application to human malaria 

 became more evident. At this stage Italian investigators, especially Grassi, 

 took up the subject, and this scientist succeeded not only in demonstrating 

 that certain species of the genus Anopheles, especially A. claviger, Fabr. 

 A. maculipennis, Meig., 1 inoculate malaria to man by means of their bite 

 just like species of the genus Culex are the carriers of proteosoma infection 

 amongst birds, bjit he also followed the development of the parasites in 

 the body of the mosquito more carefully than had hitherto been done (22). 

 The commissions- despatched for the study of malaria on the spot and 

 numerous independent scientists, gathered fresh knowledge, so that the 

 literature on the subject has acquired enormous dimensions, notwithstand- 

 ing the short time that has elapsed since the investigation of malaria 

 began. The researches as to the structure and habits of mosquitoes and 

 the methods recommended for the prevention of malaria are continually 

 being extended. Although it is most gratifying to note the large number 

 of workers engaged in the solution of the problem of malaria, which is 

 one of great importance to mankind, the occasional premature conclusions 

 arrived at, and which lead to the publication of immature work, is to 

 be deplored, as they frequently mislead more sober investigators. 



After all these works, the following facts may be briefly stated 

 in regard to the malaria parasites. What had hitherto been known 

 of them related to their schizogony and a few erroneously under- 

 stood stages, which were actually related to sporogony (crescents, 

 spheres, polymitus-form). By means of their bite certain species 

 of mosquitoes introduce the crescents and spheres into their bodies 

 with the blood. If the atmospheric temperature is sufficiently high, 

 these forms become sexually differentiated, and after the females 



1 The name claviger (Fabricius) used in Italy cannot stand. Fabricius had no type 

 of claviger. (F. V. T.). 



3 " Ergebn. d. wiss. Exped. d. Geh. Rath Koch nach Italien z. Erf. d. Malaria " (Dtsch. 

 med. Wochenschr., 1899, p. 69} ; i.-v. " Ber. ub. d. Thatigk. d. Malaria-Exp." (ibid., p. 601, 

 1900, Nos. 5, 17, 18, 25, 34, and 46); " Zusammenfass. Darst. d. Ergebn. d. Malaria- 

 Exp." (ibid., Nos. 49, 50). Ray, Annett and Austen, " Report on the Mai. Exp. of 

 the Liverpool School of Tropical Medicine,' 1 Liverpool, 1900. 



