TRYPANOSOMIASIS EXPEDITION TO THE CONGO 43 
normal cellular elements are much increased the fluid has also an opalescent or cloudy 
appearance, but there is 110 yellowish tinge. It is doubtful whether the presence of 
the parasite in the cerebro-spinal fluid has any influence upon the increase of its 
cellular elements. It would seem, from a study of our cases, that the fluid as a rule, 
whether the parasites he present or not, is perfectly clear and limpid as in health. 
Only in a few instances, in both positive and negative cases, have the cellular elements 
shown an apparent increase, consisting mainly of small mononuclear cells, together 
with some mononuclear large cells. In Case 93, the only one in which a large number 
of parasites — fifty to a cover — were found in the cerebro-spinal fluid, a great increase 
of small mononuclear cells was noted at the same time. A month later the cerebro- 
spinal fluid was again examined, but only one parasite could be found, and the cellular 
elements were scanty. This case, up to the present date, nearly two months after the 
discovery of large numbers of trypanosomes in the cerebro-spinal fluid, has shown 
no tendency to sleep during the daytime, no wasting, nor any of the more noticeable 
symptoms associated with the later stages of many of our cases of trypano- 
somiasis. 
As a rule, we have found that the parasites occur in extremely scanty numbers 
in the cerebro-spinal fluid, seldom more than one to three or four, very occasionally 
from ten to twenty to the cover-glass preparation of the sediment left after centri- 
fugalizing. 
As already stated, neither at Leopoldville, nor anywhere on the Lower Congo, 
up to the present time, have we met with a case of Congo sickness in which sleep 
has had a prominent place among the clinical symptoms, and in those few cases in 
which it has been noted a few davs before death, or at irregular intervals during the 
course of the disease, it has not been describable as deep or continuous sleep, but 
merely a drowsy or somnolent condition from which the patient was at once aroused 
by being touched or, perhaps, by being spoken to. On comparing the cases in which 
parasites were found in cerebro-spinal fluid with those in which they were not found, 
we see that most of the few cases in which drowsiness was a feature, together with 
cases in which head symptoms, e.g., mild mania, epileptic attacks, flexure contractions, 
and convulsive seizures, were conspicuous are upon the positive side. On the negative 
side similar cases are also found, but it is noticeable that there are many of those cases 
which showed hardly any symptoms, and which, if no fatal complications intervened, 
lived on month after month in an advanced state of emaciation, retaining their facul- 
ties, speech, appetite, etc., almost to the moment of their death. 
It is, therefore, not improbable that the presence of the parasites in the cerebro- 
spinal fluid at a late stage in the disease may tend to increase the gravity of the case 
by predisposing to one or other of many complications, or, in other ways, hasten a fatal 
termination ; but that this is not invariably so is proved by at least two of our cases, 
one of which (Case 93) is now one of the most sturdy patients under observation. 
