547 
a very slight degree on other kinds of blood. This last observation 
was subsequently confirmed by Lazar. 4 However, unless all traces 
of the stromata of the red cells had been removed from the 
haemoglobin solution — and this is by no means an easy performance 
—an obvious explanation for this inhibiting action of such solutions 
would be that the stromata themselves had fixed the agglutinins 
present in the horse serum, and consequently there would be little, 
if any, left to act upon the red corpuscles. Naturally, in this case, 
the inhibiting action would be specific for the variety of red cells 
from which the haemoglobin solution was made. 
The fact that the phenomenon of auto-agglutination is reversible 
allows one to approach the subject of specificity from a different 
point of view, namely, by extracting the completely agglutinated 
red cells with a small quantity of normal saline solution at 37 ° C > 
and then investigating the nature of the digest. 
Experiment. — To 10 c.c. of defibrinated plasma of Rabbit 1035 
(infected with T. brucei) were added 0'2 c.c. of the red cells of the 
same animal. After allowing the mixture to stand in the ice chest 
for twelve hours with occasional stirrings the supernatant plasma 
was decanted off, and the clumped red blood cells washed four 
times with at least ten times their volume of normal saline solution 
at o° C. ; o'2 c.c. of normal salt solution was then added to the 
agglutinated mass of red cells and the mixture allowed to digest at 
40° C. for half an hour. At the end of this time no trace of 
agglutination was visible. The red cells were then quickly thrown 
down by centrifugalisation and the supernatant fluid removed 
(Digest solution). 
A 5 per cent, suspension of red blood cells in normal saline 
solution was prepared from the following animals: Rabbit 1035 
finfected with T. brucei), normal Rabbit A, Donkey 2 (infected with 
T. rhodesiense ), normal Donkey A, Goat 1041 (infected with 
T. rhodesiense ), normal Goat A, and from a normal rat, guinea-pig, 
dog, horse, Macacus rhesus , Cercopithecus callitrichus , and human 
being. 
The capacity of the untreated plasma of Rabbit 1035 and of 
the solution prepared by digesting the agglutinated red cells with 
normal saline at o° C. to agglutinate these different erythrocytes was 
then examined. ____ 
7r Urter die Bedeutung der Upoiden Stoffe dcr rothen Blutkorperchen fur dm Mechanisms 
der Agglutination,' Wien. Klin. Woch., 1905, p. iotz. 
