212 Captain H. S. Ranken. Treatment of Human [Dec. 23, 



treatment on the numbers of leucocytes. The cases selected were all under 

 treatment, but some enumerations were made on untreated cases and the 

 same changes observed. 



Immediately after injection of antimony there is a considerable reduction 

 of the leucocytes in the peripheral blood and in half an hour they have fallen 

 to 60 per cent, of the number obtained on enumeration just before adminis- 

 tration. In some cases the count is still lower an hour after the injection. 

 From this point the leucocytes began to rise in number and in the majority 

 of cases have returned in four or six hours to the level of the first count. 

 This increase continues and 24 hours after treatment there is an average 

 count of over 16,000 ; this is maintained for another 24 hours, but four days 

 after treatment the numbers have fallen to approximately the original count. 

 The estimations were continued over a series of three doses, and showed the 

 same changes after each. 



III. Action of Antimony on Trypanosomas. 



The exceedingly rapid action of the salts of antimony in man has been 

 reported (4), but it was not anticipated that the metal would have an almost 

 immediate trypanocidal action. Trypanosomes were never found in cases 

 examined a few hours after treatment, so observations were made to determine 

 the time required for an intravenous injection of antimony to clear the glands 

 of trypanosomes. Only heavily infected cases were selected, a case being 

 considered suitable if 10 trypanosomes were found in five minutes in the 

 gland juice, but in many instances they were much more numerous, two and 

 three trypanosomes being often seen in one field. The time was taken from 

 the moment the antimony suspended in saline solution entered a vein in the 

 arm, and at periods from 3 to 30 minutes after this time glands were 

 punctured and wet preparations made. These were examined both by dark 

 ground and ordinary illumination. In all cases 15 minutes was allowed for 

 each film, and in many cases the search was prolonged up to 30 or 

 45 minutes. 



After 3 minutes (slide made before the injection is completed). — Trypano- 

 somes are still abundant, but some are already very obviously affected by the 

 treatment. They show greatly exaggerated activity and dash rapidly across 

 the field, so that they are difficult to keep in view. Frequently a trypano- 

 some becomes anchored by the blunt end and lashes about most vigorously. 

 This exaggerated motility soon passes into a state of fatigue, when the trypano- 

 some wriggles more slowly and more and more feebly till movement ceases. 

 Some retain their normal form, while others become swollen and bloated. 



