240 Dr. W. Yorke. Auto-Agglutination of [ Nov. 2, 
Advances in our Knowledge of Sleeping Sickness,’ Breinl* remarked that 
with regard to its (auto-agglutination) mechanism he had not, up to the 
present, been able to arrive at any definite conclusions. All his attempts 
to isolate a hemagglutinin had failed, and he had not been able to 
demonstrate either an iso- or an auto-agglutinin. Dr. Nierensteint had 
shown that in trypanosomiasis a definite increase of the acidity of the 
blood occurred. This was most probably due to an increase of the amino- 
acids in the blood, and Brein] and Nierenstein inclined to the view that auto- 
agelutination was caused by this excess of amino-acids. Unfortunately, they 
had not so far been able to find a definite proof of the correctness of this 
conception. 
The results obtained by these investigators are thus somewhat conflicting, 
for whereas Kanthack, Durham, and Blandford found an iso-agglutinin in the 
serum of certain animals infected with 7. brucer, Breinl was unable to 
demonstrate the existence of either an auto- or an iso-agglutinin. 
Lxanunation of Serum of Infected Animals for Auto-agglutinin.—Having 
under observation a number of animals, the blood of which when examined 
in cover-slip preparations exhibited the phenomenon of auto-agglutination to 
a greater or less degree, it was decided to perform experiments with a view 
to investigating the mechanism of its production. 
Technique.-—The blood was collected in a solution containing 1 per cent. 
sodium citrate and 0°9 per cent. sodium chloride in distilled water. The 
blood was then centrifugalised and the corpuscles washed three times in 
normal saline solution. A 5-per-cent. suspension of the washed red cells 
was then made in normal saline. Another sample of the same blood was 
collected and allowed to clot and the serum subsequently freed from the clot. 
by centrifugalisation. 
Equal amounts of the serum and emulsion of red corpuscles were then 
mixed together and drawn up into a capillary tube which was placed 
vertically in the incubator at 37° C. 
The results of such experiments may be briefly summarised. With the 
exception of a few cases in which there appeared to be a trace of agelutina- 
tion they were all negative. Similar negative results were obtained when 
the sera were examined for the presence of iso-agglutinins and also when the 
serum was replaced by citrated plasma. 
At first one was somewhat at a loss to account for these apparently con- 
flicting results, as even the sera of animals where the cover-slip preparations 
* “Trans. Soc. Trop. Med. and Hygiene,’ 1909, p. 29. 
+ “Observations on the Acidity and Alkalinity of the Blood in Trypanosome Infections,” 
‘ Annals of Tropical Medicine and Parasitology,’ 1908, p. 227. 
