ES7 
A Case of Sleeping Sickness studied by Precise Enumerative 
Methods: Further Observations. 
By Major Ronatp Ross, F.R.S., and Davin THomson, M.B., Ch.B., D.P.H. 
(Received October 15,—Read December 8, 1910.) 
(1) Lntroduction. 
In a previous paper by us, published in the ‘Proceedings’ of July 21, 
1910, B 557, we recorded our observations on this case during two and a-half 
months, and described particularly the regular periodical rises in the 
numbers of trypanosomes disclosed in the patient’s peripheral blood by 
methodical daily countings extending over that period. Our technique has 
been detailed in another paper by us on “ Enumerative Studies on Malarial 
Fever,” recently submitted to the Society. We now record our further 
observations on the case during two more months—until the patient’s death. 
A chart and a table giving daily details of the observations are attached; 
and accompanying papers by Drs. J. G. Thomson and H. B. Fantham record 
studies on animals and on the parasites themselves. We must refer also to 
a recent communication to the Society by Drs. J. W. W. Stephens and 
Fantham suggesting that the species found in this case may not be identical 
with 7. gambiense. 
The patient, a strong young Englishman, age 26, weight 154 lbs., was 
infected in N.E. Rhodesia near the River Luangwa in September, 1909. The 
trypanosomes were found in his blood in Africa on November 17. 
He was admitted into the Royal Southern Hospital on December 4. 
Daily estimation of the number of trypanosomes per cubic millimetre of his 
blood was commenced on February 16, and continued till his death on June 29, 
a period of 134 days. During that period we never failed to find 
trypanosomes. The history of the case from February 16 is recorded 
graphically on the folding chart facing p. 198. 
The patient had glandular swellings and ill-defined erythematous rashes 
on his legs at various intervals. On April 20 he had a severe attack of 
vomiting which continued for four days; in consequence he lost 10 lbs. in 
weight and was never again so well. He remained in bed onwards till his 
- death. He became progressively more drowsy, with intervals of more or less 
comparative brightness. His memory and mental powers failed steadily. 
On May 7 he developed a marked neuritis due to the atoxyl, and every 
dose seemed to aggravate the neuro-retinitis produced by the previous 
