264 
We are much indebted to the Director of the Sleeping Sickness 
Bureau (Dr. Bagshawe) for having given us references to the 
literature on the subject of such fluctuations. In the original case 
of Dutton and Ford it was noted that the parasites varied in 
numbers, and that a parallel rise in the patient’s temperature 
occurred. Manson and Daniels* chart the number of parasites 
compared with 500 leucocytes; but the error of this method is very 
large and their graph is quite irregular. They abandoned counts 
m measured quantities of blood as ‘ unreliable.’ Thomas and 
Bremit showed that in three cases of sleeping sickness the numbers 
of trypanosomes found in ‘ fresh cover-slip preparations’ varied 
irregularly from time to time. Koch, Beck, and Kleine (1909) 
remark on the irregularity of the appearance of T. gambiense in 
African natives, and state the parasites are present for two to five 
days and absent for two to three weeks. Salvin-Moore and BreinlJ 
show a graph with two undulations and a final premortal rise in 
two heavily infected rats, and give a detailed description of 
corresponding changes in the parasites. Apparently, hitherto, only 
iriegular variations in the numbers of the parasites seem to have 
oeen recognised; probably the large error due to inadequate methods 
° coun ting has disguised the regular periodicity of the variation 
s iown by more exact counts in the eleven successive undulations 
observed in our case. 
We should add that our methods enable us to detect parasites 
when they are in numbers so small that their detection by the 
01 mary methods would be exceedingly laborious. Hence if our 
case had been studied by the ordinary methods, probably only the 
rests o the 11'ses would have been visible in the chart, and it 
would have been said that the parasites had disappeared in the 
Med. Journ. May 30. ,903. 
