TRYPANOSOMIASIS EXPEDITION TO SENEGAMBIA 
5 
possessing ' horseshoe nuclei,' whether possessing sparse neutrophilic granulation or 
not, are often called ' transitional.' Whatever the name employed, the clinical fact 
remains that in malaria, the type of disease in which a ' large mononuclear increase ' 
occurs, the cells which become more numerous are those mononuclear large cells 
possessing the following characteristics: — They have slightly basophilic, finely reticular 
cytoplasm, often possessing nodal thickenings which simulate granulation. Their 
nuclei, though usually taking a deeper stain than the protoplasm, are still not 'deeply 
basophilic,' and are coarsely reticulated and often irregular in shape. The size of such 
cells varies from one-half to even four times that of an erythrocyte, and the 
proportion between their cytoplasm and nucleus varies greatly. 
Practically speaking, then, in malaria all the mononuclear elements, save the 
small and deeply basophilic lymphocytes, are increased, and it is solely for the 
purpose of presenting a simple definite clinical picture of the somewhat analagous 
changes in our cases of trypanosomiasis that we have adopted the following 
classification. 
Neutrophiles. 
Eosinophiles. 
Mast cells. 
, it i, | Lymphocytes. 
Mononuclear small cells i . 
I Eymphocytes with irregular nuclei. 
j Large lymphocytes. 
Mononuclear* large cells\ Large mononuclears. 
( Transitionals. 
The headings neutrophiles, eosinophiles, mast cells, and lymphocytes need 
no explanation. The term ' lymphocytes with irregular nuclei ' explains itself. We 
have classed as 'large mononuclears' only those cells which conform to Ehrlich's 
description, but have admitted as ' transitionals,' despite his definition, any large cell 
with a horseshoe shaped or doubled nucleus whether it contained sparse granules or 
not. 
Inoculations 
Infected material was, as a rule, diluted with approximately equal parts of the 
usual sodium citrate solution before inoculation. 
Both intraperitoneal and subcutaneous inoculations were practised. 
* The simple division of all mononuclears into two general classes, large and small, was suggested by the classification 
employed by Turk. - ) - We have endeavoured, while taking advantage of its simplicity, to retain that greater precision of descrip- 
tion ensured by a more complex classification. It will be at once seen that the division styled 'mononuclear large cells' in- 
clu.les both Ehrlich's ' large mononuclears ' and other cells for which that name cannot be employed. 
1 Turk, Klinische Untersuchungen ueber lias Vtrhalten des B/utes bci acuien Infektiomkrankhcitcn, 1898. 
