60 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
the anaemia lessens, and the autoagglutination disappears. As mentioned before, 
trypanroth caused a nephritis, therefore, the combination of these two subjects is 
fraught with difficulties. In order to obtain results both drugs have to be pushed. 
It therefore often happens that the animal acquires a severe nephritis and succumbs. 
The effects of this combination have been noticed on other trypansomes. 
The combined treatment offers a promising mode of medication, providing the 
untoward effect can be diminished or abolished. Very many of the smaller animals, 
especially guinea-pigs, have died from the effects produced by trypanroth. 
Action of Atoxyl and Trypanred on the Trypanosoma 
The action of atoxyl on the various trypanosomes has been studied, and after 
numerous observations, continued for the whole period during which the drug was 
administered, the effect appears to be as follows : — 
On administration of arsenic compounds into an animal showing numerous 
parasites in the blood the following action on the trypansomes will be noticed. For 
the first three-and-a-half to four hours, depending on the dose used, very little change 
in the parasites can be noticed. Between the fourth and fifth hour the effect on the 
trypanosomes is evident. Some parasites appear to be swollen and their movement 
is less rapid. If now a series of blood specimens be examined at intervals of twenty 
to thirty minutes the following changes will be seen. The number of slowly moving 
trypanosomes increases, many parasites will be seen to be almost motionless. The 
protoplasm takes on a peculiar ground-glass appearance, and dark granules appear in the 
protoplasm ; very often a whole series of granules one behind the other, sometimes 
in pairs or all clumped together, are seen lying between the macronucleus and the 
anterior end or distributed through the whole body of the parasite. At the same 
time vacuoles are observed, oftentimes very large. The trypanosomes become 
deformed, assuming various shapes, the most common being a kite-shaped form with 
fairly long flagellum, and a tadpole-like one with hardly any free flagellum. These 
forms especially exhibit greatly impaired movements. At the same time a noticeable 
increase of the leucocytes is discernable ; phagocytes begin to appear, very often 
groups of five to seven will be seen. Up to this time (sixth to seventh hours) 
the trypanosomes, though decreased in numbers, are still present in considerable 
quantities. Suddenly in the course of an hour the numbers may drop from forty to 
two to three to a held or less ; coincident with this is a very marked increase in the 
number ofleucocytes, especiallv phagocytes. From the ninth to the fourteenth and 
sixteenth hours the changes are less pronounced and rapid, the trypanosomes 
gradually disappear. At the eighteenth hour, provided the animal has been injected 
with the correct amount, the parasites are absent from the peripheral circulation and, 
even though the blood be centrifuged, none can be found. 
