1910. | Red Blood Cells in Trypanosomiasis. 251 
question, and then, after allowing reaction to take place for some hours, 
centrifugalising and examining the extracted serum regarding its agelu- 
tinating action on the red cells of the kind used for extraction and also 
on the other varieties of erythrocytes. 
Malkoff,* adopting this technique, arrived at the conclusion that there 
exist in goat’s serum, which is capable of agglutinating the erythrocytes of 
many kinds of animals, different specific agglutinins, each of which has 
a specific affinity for the corresponding variety of red cells. 
Experiment.—(1) One volume of defibrinated plasma of Rabbit 896 
(infected with 7. dimorphon) was extracted for 12 hours at 0° C. with an 
equal volume of the undiluted red blood cells of the same animal. (Extracted 
plasma A.) (2) Here the proportion of plasma to erythrocytes was one to 
five. (Extracted plasma B.) (3) One volume of the same plasma was 
treated with one volume of normal horse’s red cells. (Extracted plasma C.) 
A 5-per-cent. suspension of washed erythrocytes was prepared from the 
following animals: Rabbit 896, normal Rabbit 1, normal Donkeys 1 and 2, 
a normal guinea-pig, horse, Macacus rhesus, Cercopithecus callitrichus, and 
human being. 
The results indicate that complete extraction of the infected plasma of 
Rabbit 896 by its own erythrocytes and those of a normal horse does not 
completely destroy the agglutinating action of the plasma on the red blood 
cells of other animals, although it is to be noted that in most cases when the 
plasma had been extracted with five times its volume of its own red cells 
there was a marked lessening or even total disappearance of this action. 
This diminution of the agglutinating action of the plasma cannot be 
explained by mere dilution with the small amount of saline solution 
adhering to the red cells, as the plasma still caused marked agglutination 
after the addition of fifteen times its volume of 0°9 per cent. NaCl solution. 
It is doubtful, however, whether experiments of this kind really have the 
importance that has been assigned to them by Malkoff and others. 
Landsteiner and Sturlif using normal horse and dog serum and 11 varieties 
of erythrocytes, confirmed Malkoff’s observation that saturation of the serum 
with one kind of red blood cell deprived it of the power to agglutinate this 
variety, and this only. They furthermore showed that red cells which had 
already been once completely agglutinated were still able to react with 
another kind of serum, and that the new serum after the reaction had lost its 
power to agglutinate fresh corpuscles of the same kind. Hence, as 
* “Beitrige zur Frage der Agglutination von rother Blutkérperchen,” ‘Deutsche 
Med. Woch.,’ 1900, No. 14. 
+ “Ueber die Hamagglutinine normaler Sera,” ‘ Wien, Klin. Woch.,’ 1902, p. 38. 
