402 
naturally about to fall, and the rapid diminution attributed to the 
drug. 
It has been stated that atoxyl did not always cause a 
disappearance of the parasites, but that sometimes instead they 
even increased in numbers; and further, that it seemed to have a 
more marked trypanocidal action when the parasites were very 
numerous. 
I hese statements can be understood in the light of the natural 
cycle. 
Again, if the trypanosomes increase in number immediately after 
the administration of a drug, one cannot at once conclude that this 
drug is of no value as a trypanocide. 
The Effect of Atoxyl 
h rom February 16 till April 5 atoxyl was not given, on account 
"f its injurious effect on the patient’s eyes. On April 5 we, 
however, injected a dose of four grains at the commencement of 
*1 natural rise. i he blood was examined every two hours 
afterwards and showed that the trypanosomes were increasing in 
numbers. Twenty-four hours later there was a further marked 
increase. Next day again, as we would have expected to occur 
naturally, there was a decided diminution in their number. 
On May 2 atoxyl was again given, though it was found that 
every dose aggravated the eye condition. From May 2 till June 
20 * th,rt y~two grains of atoxyl in all were administered at intervals, 
as noted on the chart. On comparing the graph where no atoxyl was 
given, and where it was administered, no very appreciable difference 
,n the number of trypanosomes can be detected. We cannot, 
however, conclude that the atoxyl has no trypanocidal effect, as had 
not been given the trypanosomes may possibly have been much 
more numerous during the latter than in the earlier part of the 
r t , and further, this particular strain of trypanosomes seems to 
have been very virulent. 
Our doses of atoxyl in any case were rather small. It would 
ppear to us, however, that atoxyl cannot be considered a specified 
0 y tr Tpanosomiasis, as quinine is in malaria. In our cases 
of ma ana quinine never failed to diminish, markedly, the number 
sexua parasites. Moreover, atoxyl compared with quinine is 
a da ngerous drug. ^ 
