456 Blastocystis hominis 
be shown to arise from the nucleus. No signs of sporulation were 
found in this case. 
Case No. 3 (PI. XVII, Figs. 65-82). 
A European suffering from amoebic dysentery. 
Infection with Blastocystis combined with Chilotnastix tnesnili and 
Entamoeba histolytica. 
In this case for the first time living blastocysts (not staining red 
with eosin) were encountered. The sphere was generally much smallei 
in relation to the surrounding cytoplasm, than in the former cases 
(Figs. 70-75). The blastocysts differed also from the former by the 
presence of a vesicular nucleus, with only small chromatic granules and 
a distinct reticular nucleoplasm (Figs. 71-73); in other forms only 
peripheral chromatic granules were to be seen (Figs. 75-77). Division 
was observed (Fig. 81), but only combined with the filamentous 
differentiation of the cytoplasm already mentioned (Case No. 1). 
In Case No. 3 it was quite clear that the blastocysts were formed by 
Chilomastix mesnili (Fig. 65), which often showed near the nucleus a 
greyish coloured body (Figs. 66, 67) which by growing fills up the 
greater part of the cell (Figs. 68, 69), thus producing forms identical 
in appearance with the blastocysts shown in Figs. 71-73. 
Case No. 4 (PI. XVII, Figs. 83-95). 
Rat infected with Chilomastix and Blastocystis. Preparations 
kindly furnished by Dr S. L. Brug. 
The blastocysts in this case were characterised by the distinct vacuolar 
structure of the cytoplasmatic fringe. Divisional forms were common 
(Fig. 89) without however showing the peculiar changes, described in 
the former cases. The nucleus, when present, showed the structure 
described in Case No. 3 (Figs. 84, 85, 86, 93). Besides these nuclei, 
chromatic granules were present. Sometimes the peripheral cyto¬ 
plasm was reduced to a line (Fig. 95); other forms might suggest 
sporulation (Fig. 92) but no other stages were found supporting this 
view. 
As in the former case, the blastocysts were formed by the roimded 
forms of Chilomastix (Fig. 83) which accompanied the flagellate stages 
not figured here. These forms show a strongly vacuolated cytoplasm; 
between the vacuoles a grey structureless substance appears (Fig. 83) 
which by growing pushes the vacuoles to the periphery (Fig. 84), takes 
