

1905.] «fected wth Various Forms of Trypanosomes, 239 
Exanvnation of the Brains of Animals Infected with Trypanosomes. 
It has been stated that trypanosomes cannot be shown in sections of the 
brain, and that the hardening fluid may have been the reason why more 
definite evidence of the trypanosome infection in sleeping sickness has not 
been observed. The following observations show that both these lypotheses 
are probably untenable. 
(1) The brain of a rabbit inoculated with Surra, which died three months 
later, hardened in formol, was kindly given me by Dr. Plimmer, and showed 
the following appearances in sections. By any of the staining methods 
employed, nearly all the blood vessels showed masses of trypanosomes, as the 
coloured drawings exhibit. Single trypanosomes could be seen in the 
capillaries; in the larger vessels solitary trypanosomes, and whorls of 
trypanosomes, and plasmoidal masses, which may either be degenerated 
trypanosomes consisting of a zooglceal mass, in which more deeply stained 
macro-nuclei and micro-nuclei can be seen, or, as Plimmer and Bradford 
‘consider, of amceboid forms. But in spite of this extraordinary trypanosome 
infection, the blood vessels showed little or no inflammatory reaction. The 
peri-vascular spaces showed no lymphocytes, the ganglion cells showed marked 
chromolytic changes, otherwise there was nothing noteworthy in the nervous 
system. 
(2) The brains of two oxen infected with Jinga trypanosomes were 
examined. The animals died within three months of infection; the results 
of the examinations were extremely interesting and will be given in some 
detail. 
Experiment 162.—The cortex cerebri, the cerebellum, medulla and spinal 
cord were examined, and all yielded the same results. With a magnification 
of 1200 diameters, the capillaries and vessels were found to contain 
chromatin bodies, exactly resembling Leishman bodies, except that they were 
smaller, measuring from 1 to 2 w,much more frequently 1 yp, rarely as large as 
2. They were either circular or oval rings or had the appearance of the 
chromatin particles being situated at the two poles. Several drawings and 
photographs are given to illustrate their appearance and their numbers. 
Some of the capillaries show immense numbers, and in some transections of 
larger vessels, these bodies can be observed lying in a zoogloeal mass. 
Individual bodies exhibit some diversity in their form, indicating division. 
A large number of stained particles (which may be micro-nuclei) can be seen. 
The Jinga trypanosome, as the accompanying drawing shows, is com- 
paratively a large organism, as seen in the blood of a monkey, which was 
inoculated with it. Its oval macro-nucleus is much larger than these 
