512 



TELOSPORIDIA 



twenty to thirty sporoblasts, whose periphery will be marked by a 

 palisade of forming sporozoites. 



Between the fourth and fifth day the cysts (50 /lc in diameter) 

 full of sporozoites (size 14 /bi) Will be seen to be projecting into the 

 coelome. 



After the seventh day the oocyst ruptures, and the sporozoites 

 escape and find their way to the salivary glands, in the cells of 

 which the}^ lie, mainly in those of the mid or poison gland. Thus, 

 about the tenth to the twelfth day after infection the mosquito is 

 ready to spread the disease by its bite, and the cycle of sporogony 

 is complete. It must be remembered that Schaudinn observed 

 infection of the mosquito's f^gg, but whether the parasite penetrates 

 into the larva, and from that to the pupa, and thus into a second 

 generation, is not known. 



Plasmodium malariae Laveran, 1881 (Plate I.). 



Synonyms. — Hcemaniceba malaricB Grassi and Feletti, 1890; 

 H. laverani var. quartana Labbe, 1894; H. malarice var. magna 

 Laveran, 1900; H. malaricB var. quartancB Laveran, igoi; Plasmo- 

 dium malarice var. quartance Celli and Sanfelice, 1891; Hcsmospor- 

 idium quartancB Lewkowicz, i8gy; Plasmodium ma-aricB quartanum 

 Labbe, 1899; P. golgii Sambon, 1902; Laverania malaricB Jannesco, 

 1905; and Oscillavia malarice Laveran, 1881. 



Schizogony. — ^The young trophozoite, which is smaller than 

 P. vivax, forms a compact ring, which lies in an unaltered erythro- 

 cyte, and shows, as a rule, but little pseudopodial activity. Very 

 soon hsemozoin appears in the form of dark rodlets. 



After the first twenty-four hours the parasite is found to be much 

 larger, and the hsemozoin more abundant. The granules of pig- 

 ment will be noticed to be gathered at the periphery, and to be 

 very dark in colour, and non-motile. The red cell tends, if any- 

 thing, to become smaller and darker. In about sixty hours the 

 trophozoite will have become the full-grown schizont, which is a 

 large, round, pigmented body surrounded by a rim belonging to 

 the corpuscle. During the next twelve hours its nucleus divides up 

 into six or twelve nuclei, around which the cytoplasm gathers, while 

 the hsemozoin is driven into the centre, and the appearance of a 

 daisy is produced by the central block of hsemozoin and the regular 

 arrangement of the merozoites around it (size 6 /^). 



The merozoites (size 175 (jl) are now set free, and, as a rule, many 

 of them appear to be killed off, and not to be able to affect the red 

 cells. More rarely they go on increasing in number, and recently 

 have been said to cause death in a case (Leishman), but a severe 

 infection is not usual. 



The whole schizogony takes place in the peripheral blood, and 

 occupies seventy- two hours. 



Sporogony. — Gametocytes are very rarely seen, and only after 

 the disease has lasted a long time, but Vida has recently described 

 all stages of their development as seen in the peripheral blood. 



