388 Major W. B. Fry and Captain H. S. Ranken. [Dec. 23, 



" Histological Observations on Sleeping Sickness and other Trypanosome 

 Infections." 



VII. Some Animal Experimental Work in Reference to Granules. 



A number of experiments were undertaken to ascertain if it were possible 

 to infect animals by granules alone. To do this, fluid containing granules and 

 no trypanosomes was required. It was thought possible that the granules (if 

 reproductive elements) might prove more resistant to changes in their 

 environment than adult trypanosomes. In order to test this, blood showing 

 a heavy infection was added to a hypertonic salt solution, up to 2 per cent. 



It was found on mixing one volume of infected blood with two to three of 

 salt solution and keeping it at temperatures between 34° and 38° C, that 

 after standing for 5 to 10 minutes individual trypanosomes began to swell 

 up and become globular and the contained granule or granules to become 

 active, moving about in the now spherical trypanosomes ; after a short period 

 the granules escaped from the containing membrane and became free. The 

 remnant of the trypanosome was left as a faintly discernible spherical body 

 with no characteristic features. 



This process of escape of granules continued until no formed trypanosomes 

 could be found ; at the end of from half to three-quarters of an hour the 

 process, as a rule, appeared complete. There are apparently several factors 

 which influence the occurrence of this phenomenon, the temperature, the 

 hypertonicity of the solution, tbe stage of development of the trypanosomes, 

 and the strain worked with. 



If, whilst looking at one of these slides during the process, an individual 

 trypanosome be watched, it will be noticed that its active movements 

 suddenly become slowed, and then, as though blown steadily out by some 

 entering fluid, the trypanosome, in the course of about 3 to 10 sees., is 

 changed from its usual shape to that of a round body in which the granule 

 or granules are freely motile. The escape of the granule takes place, as 

 a rule, a few minutes after this. 



Infection was obtained repeatedly, and the following are details of two 

 positive results : — 



No. I. 



November 5. — Gerbil (F. 10) injected with about - 2 c.c. of treated blood obtained 

 from a gerbil infected with T. nanum (heavy infection). The injected blood was treated 

 with sodium chloride solution 2 per cent, and sodium citrate 1 per cent, for one hour. 

 At the moment of injection no living trypanosomes could be distinguished ; sphere forms 

 and free granules very numerous. 



November 10. — Trypanosomes first found in blood. 



November 11. — Trypanosomes very numerous. 



November 14. — Gerbil found dead : spleen very large. 



