495 
relatively large. The doses given may have had a slight 
trypanocidal action, but from the appearances of the smears we do 
not think there was any marked degeneration, and many 
trypanosomes were found actively dividing. The doses gi\en to 
this animal would, if calculated to the body weight of a man of 70 
kilograms, represent approximately 38 grains, 16 ;o grains, an 
2514 grains. The lengthened period between the crests of the 
waves may have been caused by natural body resistance being raise . 
This animal lived twenty-seven days, whereas the longest peno 0 
life recorded in our controls, sub-inoculated with the same s 
was eighteen days in an animal weighing 48 grams. 
If we examine now Rat 35. which was treated with similar doses 
of atoxyl, and kept in the cold chamber, we find quite a 
character in the graph representing the numbers o ti>pano 
in the peripheral blood. This animal was piebald in c0 011 1 
weighed 14s grams, that is to say, it was only digit \ lca ' 1 ^ 
Rat 34. This means that the doses given when calculated to M 
weight of a man were smaller than those gi\cn to at 3 
doses would represent in man 8 04 grams, 160b g ra ““ j 
^ains. In spite of these doses the tryP—' »* ^ 
circulation rapidly increased in numbers wi num ber of 
- «»• 1 , u. rvr 
570,000 per c.mm. of blood. 1 his a It cannot be 
and received during that time ten doses o ‘ ^ had an)' 
said in this case that the atoxyl m ' e ^ ^ an imal was 
trypanocidal action, but, again, the 1 * f division forms 
undoubtedly prolonged by the drug. “ "V, pro liferation of the 
seen in the smears of this animal showed tn« - the - propo rtion 
trypanosomes was very active, and we also noted that 
°f short, stumpy forms was also maike ) in chamber with 
Rat 36, white in colour, and treate . fl many respects 
small doses of atoxyl, shows a char ^ ^ the staircase 
simulates the chart of Rat 35 - Here, a f a1 ^ trea tment with small 
rise of the trypanosomes in spite of continue Ratg ^ a nd 35 - 
doses of atoxyl. This animal being ieaU . tQ the body weight 
received, therefore, doses which, when ca cu era j n s, 9' 28 £ rain9 
°f a man, were relatively small, name), 
and 1 3 92 grains. 
