H. E. Durham 
231 
weight record showed a continuous steady gain in weight since the 
inoculation. 
On the other hand, progressive wasting and local swellings make a 
rabbit into a truly melancholy sight long before death supervenes, yet 
even with the aid of the centrifuge, the presence of trypanosomes may 
not be discoverable, until within a few days of death. The following 
example may be cited : a rabbit (2650 grams) was infected with a 
needle wetted with infective blood, 28 days later the weight had fallen 
to 1440 grams, the nose and eyelids were much swollen and obstructed. 
It was killed and its tissues searched for the presence of trypanosomes. 
The blood revealed none, in fact the only place where the parasites were 
found was in the rib marrow, and there they were quite sparse. Bone 
marrow in other regions was examined with negative result. It might 
be thought that the presence of the parasite in so important a tissue as 
the rib marrow might be significant to explain the disease, were it not 
that the trypanosome occurs in great numbers in the similar marrow of 
the rat. It is, perhaps, not inapt to remark that in malaria, the mature 
or almost mature parasites do not assert their presence with the marked 
disturbance of health, which is caused by the shower of a young brood 
through the system. 
In animals, especially when they are near unto death from 
nagana disease, the blood shows marked morphological changes; the 
red blood corpuscles are reduced to about half their proper number, 
the leucocytes may be considerably increased, and nucleated red 
corpuscles are to be found. In my experience nucleated red corpuscles 
appear more abundantly in the rat and mouse than in other animals. 
Thus on one occasion the blood count of a rat, which was moribund, 
gave the high figure, 4,500 nucleated red corpuscles and 28,500 leuco¬ 
cytes per cubic millimetre. At this late stage of the disease the red 
corpuscles do not run well into rouleaux but tend to aggregate into 
small clumps. This clumping of the red corpuscles is evidently due to 
an alteration in the plasma or serum, for healthy corpuscles are caused 
to aggregate in a similar manner by mixing them with the diseased 
serum. 
In some respects, nagana recalls the condition known as pernicious 
anaemia in man ; and it may be noted that in 1897, I inoculated 
several rats with blood taken from patients suffering from this com¬ 
plaint. Cases are rare and I was not successful in trying from a case, 
which had not had arsenic administered therapeutically. At the same 
time several rats were injected with blood from patients suffering 
