49 6 
In this animal all the smears gave evidence of the trypanosomes 
being abnormally stimulated to division. Many of the trypanosomes 
were seen to be dividing into four, and the numbers before death 
reached 530,000 per c.mm. of blood. 
This animal lived twenty-seven days. If we do not attribute 
the prolonged life of these three rats to the trypanocidal action 
of the atoxyl we must endeavour to explain it in another manner. 
Arsenic in small doses affects metabolism and improves the 
general condition of the body. In small doses we find in man, both 
in health and disease, that the strength, weight and appetite are 
improved, and it is quite to be expected, therefore, that small 
repeated doses of atoxyl in rats would tend to raise the natural 
body resistance. In referring to Cushny’s Pharmacology we find 
that Gies treated young rabbits with arsenic, and found that those 
treated weighed more, had larger bones, and more developed 
muscles than the untreated controls. It was also found that a 
pregnant female rabbit treated with arsenic gave birth to young 
rabbits of abnormal size. That arsenic, therefore, in small doses 
profoundly affects metabolism and improves the general condition 
we have good evidence, and this might possibly explain the 
lengthened life of the animals treated with atoxyl in small doses. 
In the same way the lengthened period between the crests of the 
waves in Rat 34 may possibly have been due to increased resistance 
of the body of the host rather than to a direct action of the drug 
administered upon the parasites. 
In spite of the fact that the animals’ lives were prolonged we had 
the trypanosomes increase steadily in numbers, and this was very 
marked iji the cases of Rats 35 and 36. The numbers of 
trypanosomes in the peripheral blood remained consistently high, 
and the smears showed very active divisions of parasites. This can 
be attributed to the action of the atoxyl in small doses. We have 
already referred to the general action of arsenic in small therapeutic 
doses. The drug seems to act as a tonic to the body in health as 
well as disease, and must, therefore, improve the condition of the 
cells of the whole body. Stockman and Greig* found the bone 
marrow in a state of unusual activity when arsenic was administered 
Sec Cushny’s 1 Pharmacology ' on actions oftarsenic. 
