248 Dr. W. Yorke. Auto-Agglutination of [Nov. 2, 
plasma of normal and infected animals were heated in a water bath to 
58° C. and 70° to 72° C. respectively for 20 minutes. Heating to 58° C. 
was found not to destroy auto-agglutinin, whereas plasma which had been 
subjected to a temperature of 70° C. for 20 minutes had completely lost this 
property. 
Significance of the Phenomenon in Trypanosomal Infections—The question 
of the mechanism of production of auto-agglutination in trypanosomal 
infections is one which has frequently been discussed, but as yet no satis- 
factory explanation has been offered. With reference to this question it 
appears to me that two theories might be advanced to explain the develop- 
ment of an excess of auto-agglutinin in this disease. 
It has long been recognised that the blood of men and the lower animals 
suffering from trypanosomiasis is frequently very anemic. Both the 
percentage of hemoglobin and the number of red corpuscles per cubic 
millimetre fall to a low level. This is particularly the case in the last stages 
of the disease. Conceivably auto-agglutinin might develop in the plasma as 
a result of auto-inoculation of an animal resulting from the destruction of its 
own erythrocytes. 
There are, however, many considerations which operate against this view. 
In the first place I have found no constant relation between the development 
of anemia and auto-agglutination of the red cells. By the aid of systematic 
hemocrit examinations of the blood of recently infected animals it was 
observed that auto-agglutination was usually pronounced for a considerable 
period before any marked fall of the hemocrit value had occurred. Secondly, 
a marked degree of auto-agglutination comparable to that occurring in 
trypanosomiasis has not been described in any other of the diseases in which 
anemia is a distinctive feature. Dudgeon* examined the blood of 26 cases 
of anzmia due to various causes without finding a single example of auto- 
agglutination. It is doubtful, however, whether the technique adopted by 
Dudgeon is suitable for the recognition of small amounts of auto-agglutinin. 
Then again it is generally recognised as impossible to evoke the production of 
auto-bodies experimentally by inoculating an animal with its own tissues. 
Experiment—A. rabbit was injected intraperitoneally with 10 c.c. of its 
own erythrocytes which had been laked with distilled water and the resulting 
solution made isotonic with sodium chloride. This injection was repeated 
after an interval of a week. No increase of auto-agglutinin was found to 
occur in the animal’s blood. ) 
Another possible explanation for the cause of the development of auto- 
* “On the Presence of Hemagglutinins, etc., in the Blood obtained from Infectious 
and Non-infectious Diseases in Man,” ‘ Roy. Soc. Proc.,’ 1909, B, vol. 80, p. 531. 
