24 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
citrate is added, must of necessity be of no value for agglutination diagnosis on 
account of spontaneous agglutination of the parasites. With defibrinated blood the 
objection is that the agglutination of the blood corpuscles seen so often in animals or 
man suffering from trypanosomiasis renders it impossible to say whether a true 
agglutination of the parasites is produced. 
Serum from the horse, cow, donkey, sheep, or goat, if added in large quantities, 
produce an agglutination ; it is perhaps a trifle more marked if the animals have been 
infected 1 or cured. Baboon serum agglutinates the parasites to a certain extent, the 
action seems to increase and remain, as far better agglutinations are observed some 
hours after the commencement of the experiment. 
Conclusions 
1. The further comparison of the trypanosomes found in (#) the cerebro-spinal 
fluid of Uganda sleeping sickness cases; (b) the cerebro-spinal fluid and blood of the 
Congo Free State sleeping sickness cases ; (c) the blood of Congo Free State 'Trypano- 
some Fever' cases ; and (//) the blood of Europeans infected in the Congo confirms the 
previous observations that all these trypanosomes are identical in animal reactions and 
morphology with Trypanosoma gambiense (Dutton). 
2. There is no acquired immunity against infection nor transmission of immunity 
to offspring. 
3. That baboons, Cynocephalus babuin and Cynocephalus sphinx, are susceptible to 
infection with T. gambiense. That usually a chronic type of the infection develops 
but a fatal termination occurs. 
4. That in many of the animals, especially the horse, cow, donkey, sheep, and 
goat, the infection is of a mild character, but their blood is still infective to susceptible 
animals one year after the infection. That in the case of the horse the parasites are 
still occasionally seen and the blood infective twenty-eight months after inoculation. 
5. That periodicity of the parasite is a prominent feature both in man and 
beast. 
6. That the passing of a strain from a susceptible into a very resistant animal 
does not attenuate the organism. 
7. That the parasites in an animal may sometimes become more virulent. The 
numbers increasing enormously, the subinoculated animals become more rapidly 
infected and death occurs. That such a strain may be particularly virulent for one 
species of animal. That the more rapid infection is not due to the inoculation of a 
greater number of parasites than usual. 
8. That the parasites, after being passed through many hundreds of animals for 
nearly three years, still retain its morphological characters,, and animals inoculated with 
it react as described by Dutton and Todd. 2, 
1. The sera from animals infected with other trypanosomata usually cause almost as much. 
2. Liverpool School of Tropical Medicine, Memoir XI. 
