KBl’OKT OK TKAVELUNG I'ATHOJjOOIST AND PllOTOZOOLOOiST 
14 !) 
Fresh blood preparations observed for several hours showed no change other than the 
slow movements mentioned above. Eventually these ceased, and the parasites died. Thinking 
that as these were parasites of cold-blooded animals, the conditions of microgamete formation 
might differ from the process as it occurs in the parasites of birds, blood was mixed with 
a solution of sodium citrate acidified with citric acid. This caused the male gametocytes 
to become very active. The granules streamed rapidly about the cell, and the whole parasite 
contracted to a spherical body. At the same time a kind of revolving movement of the whole 
parasite commenced, and this, with slight changes in shape, eventually ended in a rupture of 
the corpuscle and the escape of the parasite to the exterior. The granules of pigment now 
moved more rapidly than before. The parasite remained attached to the broken-down host¬ 
cell, which became paler owing to the solution of its haemoglobin in the plasma. After the 
“ dance ” of the pigment granules had gone on for a short time, microgametes were formed to 
the number of five. These remained attached to the body of the parasite and lashed about for 
some time, finally freeing themselves and swimming away out of view. The whole of this 
process closely resembles the formation of the microgametes in Jlcdtcridiimi and other similar 
parasites. In the case of the female gametoc.yte there was a change in shape, the parasite 
becoming more spherical. On no occasion did I see the gametocyte leave the host-cell. 
Fertilisation was not observed, but in a number of instances two small bodies were seen in 
the corpuscle near the parasite. (Plate XV., fig. 12.) These may have something to do with 
the maturation of the female gametocyte. The process of microgamete formation is illustrated 
in Plate XV., fig. 14. 
Examination of stained films reveals little more than has been described from the fresh 
blood. The different forms described above are again encountered. The nucleus of the 
parasite varies from a single grain of chromatin in the smallest forms to a group of chromatin 
grains in the larger. In the male gametocyte (Plate XIII., figs. 1, 5) the chromatin is in 
the form of fine granules distributed about the middle of the cell. In the female gametocyte 
(Plate XIII., figs. 4, 7) there is a collection of granules more compact than in the male 
cell, and one granule is frequently seen larger than the rest, just as occurs in the female 
gametocytes of Halteridium. It will be seen from the figures that the female gametocytes 
stain a deep blue colour, while the male gametocytes stain a pale blue or lilac. Fig. 5 is a 
male gametocyte contracted to a spherical body prior to escape from the host-cell. The young 
forms are shown at figs. 9, 10. These are flame-shaped, and in the parasite depicted at 
tig. 10 is seen a vacuole which is frequently met with in these young stages. The dimension 
of the full-grown gametocyte, male and female, is generally 14/i in length by 4p in breadth. 
The red cells of the host vary from 13 to 18/i in length. 
Little change is produced in the red cells by the parasite. The nucleus is slightly 
displaced, and the corpuscle remains unaltered in shape. The variation in the measurements 
of the uninfected red cells covers any alteration in size of the corpuscle which the parasite 
may jn-oduce. In this and in other features the parasite shows marked similarity to 
Halteridium of birds. 
A prolonged search through the films revealed a few forms which may be interpreted as 
schizonts. Two such forms are illustrated in Plate XIIL, figs. 3, 8. They have the 
chromatin scattered, and the pigment is more or less concentrated at the centre. They look 
like schizonts preparing for schizogony, but in no instance was there seen a parasite which had 
broken up into merozoites. Since young forms are frequently encountered in the blood some 
form of multiplication must l)e taking place. The only forms met with, besides the j'oung and 
full-grown gametocytes, are these bodies with several cliromatin granules. It is possilfie they 
represent male gametocytes preparing for microgamete formation, but the size of the parasite 
(fig. 3) is against this view. Unless these are schizonts. we must assume tliat some form of 
Gametocytes 
Appearances 
in the stained 
blood 
Schizonts 
