154 
KKPORT OF TRAVELLING FATHOJjOUIST AND PKOTO^iOOLOUIST 
Schizogony 
cycle in 
the liver 
Formation of 
inerozoites 
In the liver, however, very different appearances are met with. In this organ the parasite 
is found to he multiplying rapidly hy a process of schizogony. The smallest forms 
encountered are little spheres of protoplasm within the liver-cell, and having a diameter 
of 4'2/(. These liodies hear a close resemhlance to the young stages of Coccidia. As in the 
case of the Coccidia, they are frequently seen lying in a kind of vacuole in the liver-cell. 
These young schizonts, for such they are, increase in size. In a more advanced stage two 
types of schizont may be differentiated, according to their shape. One is oval in outline 
(Plate XII., fig. 31), the other is more circular in outline (Plate XIII., figs. 23, 24). When the 
schizonts have reached a certain stage in their develojiment, the nuclei commence to multiply. 
The nucleus consists of a pale-staining sphere, with a membrane in the centre of which is 
a deeply-staining karyosome. The nucleus divides hy a form of mitosis, which very much 
resembles the division of the micronuclei of Infusoria (Plate XII., tigs. 23, 24). In one 
form of schizont, which is probably the one of oval contour, the nuclear multiplication 
proceeds till alfout eight to sixteen nuclei are present (Plate XII., tig. 28). When this stage 
is reached, segmentation of the protoplasm takes place with the formation of a corresponding 
number of sausage-shaped bodies, which may be merozoites (Plate XII., fig. 27). Each of 
these merozoites has a nucleus with a distinct karyosome. In the case of the second kind 
of schizont, nuclear multiplication proceeds much further, with the result that an enormous 
number are produced (Plate XII., fig. 25). The nuclei are irregular in shape, and consist of 
a closely aggregated mass of chromatin granules. No definite karyosome can be distinguished. 
How nuclear multiplication takes place in these large schizonts has not been clearly made 
out. In the early stages, nuclear division appears to proceed as in the first kind of schizonts 
described above. Later each nucleus appears to be a mass of chromatin granules which 
becomes elongated and roughly constricted at the centre, giving rise to the irregular nuclei of 
the large schizonts. Prom the mass of protoplasm over the surface of which the nuclei 
are arranged there grow out finger-like processes of the protoplasm (Plate XII., fig. 30). 
Into each process passes one of the nuclei, which at the same time elongates, becoming much 
narrowed. Finally there are formed a large number of the narrow liaBmogregarines which 
were first encountered in the blood. They are at first arranged regularly within the 
enveloping membrane (Plate XII., fig. 29), but later they have the appearance of a tangled 
mass (Plate XII., tig. 32). From the account of the two processes just given it seems as if 
two forms of schizogony are taking place —one resulting in the formation of macromerozoites, 
the other in micromerozoites. In each case, as the schizont enlarges, the liver-cell becomes 
very much distended, till finally there is nothing left but a membrane surrounding it, while 
at one side can l)e distinguished the nucleus of the liver-cell (Plate XII., fig. 31). The 
micromerozoites are very uniform in size, but there is some variation in the size of the 
macromerozoites. 
The cysts containing the merozoites were examined in the fresh condition, and the 
appearance is figured in Plate XV., figs. 10 and 13. If the cyst is ruptured hy pressure on 
the cover slip, it is seen that the merozoites, both the large and small, crawl about exactly 
like hiemogregarines. Though the wanderings of these were followed for a considerable time, 
nothing like a sexual process was seen to take place. The micromerozoites passed over and 
under the macromerozoites and vice versa with the utmost impunity. Had they been 
differentiated gametes or anything of that kind, it would hav'e been expected that some reaction 
would have taken place between them. 
The occurrence of the two forms of schizogony in the liver with the production of the 
micro- and macro-merozoites is especially interesting, as only the micromerozoites are met with 
in the peripheral blood. It would appear that the macromerozoites live only in the liver-cells and 
there reproduce by schizogony, while the micromerozoites reproduce in the same manner and 
