412 Major K. Koss and Mr. D. Thomson. Sleejnng [May 2, 



Hospital, Liverpool — with the result that the investigations referred to were 

 commenced by Dr. David Thomson and myself from the beginning of this 

 year. As I expected, methodical counting of the parasites has at once 

 verified or disclosed several facts of importance in connection with malaria 

 and trypanosomiasis. "We now limit ourselves to a brief description of the 

 remarkable periodical increase of Trypanosovia gamhiense revealed by careful 

 daily counting in a case in my clinic (the case, which is still under treat- 

 ment, will be fully reported elsewhere). 



W. A., male, aged 26 years, a strong young man born in Northumberland, 

 was infected in N.E. Ehodesia in September, 1909, the trypanosomes 

 being found in his blood in Africa on November 17. On coming to 

 Liverpool for treatment he was admitted into the Southern Hospital on 

 December 4. From then until February 16 (73 days) the number of 

 trypanosomes in his blood was estimated only by the rough methods in 

 common use ; that is, by the proportion of trypanosomes to red cells or 

 leucocytes, or to " fields " of the microscope examined. These methods are 

 obviously open to such great error that they can scarcely be depended upon 

 to indicate any but A'^ery large differences in the numbers of objects counted. 

 During the 73 days 46 counts were made ; but on several occasions none was 

 attempted for three or four days in succession — so that, even if the methods 

 of counting employed had been more accurate, sudden fluctuations might 

 easily have been missed. Hence, as was to be expected, the graph during 

 this period is very irregular and almost worthless. On admission on 

 December 4 the patient was reported to contain about 6000 trypanosomes 

 per cubic millimetre of blood, and large numbers, amounting to about 

 3000 per cubic millimetre, were found on December 17 and 28 and on 

 January 16. All this time the patient was given tlie usual treatment with 

 atoxyl and mercury, and received altogether 10 doses of two to four grains 

 of the former. Nevertheless the parasites never fell below about 200 per 

 cubic millimetre in number, as rouglily estimated. 



It was then found, however, that atoxyl was injuring the patient's sigbt (as 

 sometimes happens), and otlier treatment was substituted. At the same 

 time we elaborated a much more correct method of counting all the 

 parasites in measured quantities (one quart-er to 1 cubic millimetre) of blood 

 taken in thick film; and from February 16 onward the patient's trypano- 

 somes were estimated daily by this method Ijy one of us (D. T.). The 

 attached chart gives the remarkable graph obtained up to the present 

 (April 30). 



Tlie nuinbers of trypanosomes found were scru])ulously recorded, and the 



