1912.] On the Extrusion of Granules by Trypanosomes. 383 



phase of hyperactivity has passed. It is then more usual to see the more 

 gradual escape of the granule, and as the trypanosomes are " anchored " the)' 

 can be kept under observation more easily. On several occasions where 

 death has occurred slowly we have been able to watch a trypanosome for 

 periods up to four hours. In the 20-minute preparations trypanosomes have 

 never been found, but granules are very numerous. The activity of the 

 freshly extruded granules after antimony is much greater than the movements 

 of granules seen before treatment. 



IV. The Free Granule. 



The granule free in the blood or fluids is seen to be a small spherical or 

 pear-shaped body. In dark-ground preparations it is seen to be highly 

 refractile, and by its activity it causes considerable disturbance in the 

 surrounding fluid ; with vital staining this young granule takes on the stain 

 rapidly and uniformly, and seems to be undifferentiated. It frequently 

 remains near its former host for some little time before showing independent 

 movement. At first only a dancing movement may be seen ; this, however, 

 is a preliminary phase, and soon the granule begins to move slowly across 

 the field, turning over on itself. There is no doubt as to the motility : they 

 have often been observed to move out of a microscope field in preparations 

 where there was no question of currents, etc. In our opinion a pseudopodial 

 protrusion appears early, which at first is short and rather thick. 



In animal infections and in cases of sleeping sickness in man, granules 

 are found in the blood, glands, and internal organs. They are, of course, 

 much more numerous in animals in which the adult parasites appear in 

 great numbers. In experimental animals granules have been found in the 

 proximal glands 24 hours after inoculation. This fact seems to be of great 

 importance. 



The criterion in the recognition of granules must be motility,* but their 

 greater affinity for such stains as toluidin blue is of undoubted assistance in 

 distinguishing them from the countless small bodies seen in wet preparations, 

 e.g. blood-platelets and leucocyte granules. 



V. Further Development of Granule. 

 So far we have shown that the trypanosome discharges living elements 

 endowed with motility, and showing the same reaction as nuclear material to 

 toluidin blue. The further stages are more difficult to follow, as all stages 



* The addition of a small quantity of cherry-gum solution to the preparation will 

 differentiate between Brownian and vital movement. It stops the former and slows the 

 latter. — H. G. Plimmer. 



