TELOSPORIDIA 



pigment and cytoplasm undivided. The cyst, now enormously en- 

 larged, bursts, and the sporozoites escape into the coelome of the 

 insect, which in this case is a hsemocoele, and therefore they enter 

 the blood, and are carried by it probably all over the insect's body. 

 Certainly they are seen in the thoracic muscles, but finally they 

 find their way to the salivary glands, and so to a new host, or 

 according to Schaudinn to the eggs, and so probably to a new 

 generation of mosquitoes. 



Sporogony takes about ten to twelve days, during Which the 

 mosquito will have sucked blood three or four times. 



Abnormal Forms. — In mosquitoes, whether infected by malarial 

 parasites or by Proteosoma, peculiar bodies, called ' black spores ' 

 by Ross, are sometimes found in the stomach wall, which are now 

 known to be protozoal parasites of the genus Nosema, which have 

 invaded the oocysts, and are therefore hyperparasites. 

 Cultivation. — Plasmodium malarice, P. vivax, and Laverania 

 malaricB were first cultivated by Bass, 

 alone and with John. They grow anae- 

 robically in blood|mixed with dextrose 

 at 41"^ C, but the^blood must have no 

 leucocytes if more than one generation 

 is to be cultivated. The whole asexual 

 cycle of P. vivax and L. malarice has been 

 completed in vitro in the corpuscles of 

 human blood. Forms suggesting par- 

 thenogenesis Were seen. 



Animal Hosts.— Although species of 

 Plasmodium exist in animals, still there is 

 no evidence that the human parasites live 

 in any other animal than man. Fermi 

 and Lumbau^ in 1912 have tested this 

 with regard to bats, sparrows, owls,' quails, and frogs, with 

 negative results. 



Classification.— A number of species, increasing gradually, belong 

 to this genus, among which are two of the malarial parasites, P. vivax 

 and P. malarice. 



Plasmodium vivax Grassi and Feletti, 1890 (Plate I.). 



Synonyms. — Hcemamceha vivax Grassi and Feletti, 1890; H. mala- 

 rice var. magna Laveran, 1900 ; H. malarice var. tertiance Laveran, 

 1901; Plasmodium malarice var. tertiance Celli and Sanfelice, 1891; 

 P. malarice tertianum Labbe, 1899; Hcemosporidium tertianum 

 Lewkowicz, 1887. 



Plasmodium vivax is the parasite of tertian malarial fever, and 

 derives its specific name from its energetic amoeboid movements, 

 which probably take place for purposes of nutrition. 



Its schizogony has been Well studied by Golgi and Schaudinn, 

 and its sporogony by Grassi, Bignami, and Bastianelli. 



The v/hole process of the schizogony of P. vivax can be sum- 



FiG. 170. — An Oocyst 

 SHOWING Ross's ' Black 

 Spores/ now known to 

 BE Protozoa belonging 

 to the Genus Nosema. 



(After Grassi.) 



