94 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
Explanation of Signs 
+ + + Very numerous, fifty or more to a field. 
+ + One or more to a field. 
+ Fairly numerous. 
— Scanty, 
o Absent. 
p. Periodicity, the parasites disappearing or diminishing to 
reappear or increase. 
Example (-, p, - , o, read : — 
' + ,' the parasites were fairly numerous at first. 
' p,' periodicity then occurred, the numbers diminishing or disappearing to reappear. 
' - ' the parasites became less numerous, and 
' o ' at death the blood was negative. 
Unless ' o ' is recorded, understand parasites seen at death. 
From these figures it is evident that the results of the inoculations of our many 
different strains are absolutely opposed to those of Plimmer. As noted before, the 
strains used by Plimmer are two of those used by us and Professor Laveran. The 
record of the direct inoculations and sub-inoculations of blood from ' Kitambo,' and of 
blood and cerebro-spinal fluid from ' Tomi,' show that no such a feature as no 
trypanosomes appearing in the blood but in the spinal cord, and later on, paralysis 
occurring was observed. 
Mr. Plimmer claims that in man the organisms are sometimes entirely confined 
to the nervous system. Careful examination of the blood in such cases would reveaj 
the parasites. As pointed out under Periodicity of the Parasite in the Natives 
(see p. 10), the daily examination of the blood for many days is necessary before 
such a decision can be arrived at. 
Until Mr. Plimmer can show that he has been able to obtain his original results 
on a large series of rats inoculated with the Uganda and other strains of Sleeping 
Sickness, the question may well be raised : ' Must such a dogmatic conclusion, as this 
result of only seventeen experiments, be accepted as to the differentiation of the 
parasite of "Uganda" Sleeping Sickness from that of " Gambian Fever"?' The 
figures of this laboratory are entirely opposed to such a conclusion. 
