TRYPANOSOMES, TRYPANOSOMIASIS, AND SLEEPING SICKNESS 61 
My colleague, Dr. Breinl, and myself have observed a large number of 
experiments, examining the animals every one-and-a-half hours until the four-and-a 
half hour, then every half hour until the parasites were almost absent, and continuing 
the observations hourly until the twenty-fourth to thirty-second hour after starting 
the experiment. From a series of these observations, we have determined that in 
hardly any of the forty-six continuously observed animals were parasites to be found 
after the eighteenth hour. Should, however, the drug be given in smaller amounts 
the process takes longer, lasting from thirty-six to forty-eight hours.' 
Phagocytosis has been observed on three occasions. We have witnessed the 
engulfing of a trypanosome still alive though almost motionless, and on other 
occasions the ingesting of dead trypanosomes. 
Observations on the effect of Trypanred on the trypanosomes show that almost 
the same changes take place, though the process is somewhat slower, usually 
requiring forty-eight hours or more ; leucocytosis also appears to be very marked in 
animals treated with this drug. 
Leucocytosis 
In the observations on the action of arsenic and trypanroth on the trypanosomes, 
it was noticed that a marked increase of leucocytes occurred. Phagocytosis having 
been seen, it was determined to try the effect of hyperleucocytic agents on the 
parasites. In the work on the effect of diphtheria antitoxine on trypanosome-infected 
animals a certain amount of leucocytosis had been observed, but it was not marked. 
Advantage has, therefore, been taken of such agents as nuclein (this also affects the 
kidneys). Thanks to Professor Sherrington, we were able to try the effect of 
colchicine on the infected animals. This substance causes a leucocytosis, but it only 
produces an increase of some six thousand in thirteen hours. Nucleinic acid acts in 
the same way. We have been induced to try the effect of administering the atoxyl 
or trypanred, or the combination atoxyl-trypanred, and following this treatment with 
the hyperleucocytic agent. Unfortunately, no better effects have been observed. 
This line of work ought not to be neglected, as it is quite evident that the leucocytes 
play a role in the decrease of the parasites. Animals which have been carefully 
observed every day show from time to time a decrease in the number of parasites in 
the peripheral blood. If the decrease be sudden and marked a vast increase in the 
number of leucocytes is determinable. 
The Action of Bacteria upon Trypanosomes 
It has been noted in animals suffering from trypanosomiasis that should a localized 
abscess occur a certain decrease in the number of trypanosomes in that region can be 
made out. In rats the tail from snipping or pressure may become ulcerated or 
I. Blood films were m;ide before beginning the experiment, and at every examination. The results of the examination 
of these stained films bear out the observations on the fresli blood films. The significance of the granules seen an I the 
phagocytosis will be discussed in a fuller report. 
