5 -» n 
employed. The plasma obtained in this way frequently dotted, 
but the process was sufficiently retarded to permit of the previous 
separation of the red corpuscles. No appreciable difference between 
the agglutinating action of the defibrinated and citrated plasma was 
observed. 
I he results of this investigation of normal blood for 
auto-agglutinin may be summarised by stating that small quantities 
of auto-agglutinin were found to be present in the blood of rabbits 
(14), guinea-pigs (4), goats (3), dogs (2), horses (4), donkeys (2), 
monkeys (Macacus rhesus) (2), and C cr to pit heats calli trie hits 
Sometimes, especially in goats and guinea-pigs, the amount present 
was exceedingly small, and considerable care was necessary to 
demonstrate its existence. In these cases a larger volume of serum 
was used in proportion to the amount of red cells and the reaction 
allowed to proceed for a longer period. It is to be observed that 
clumping ol the erythrocytes only occurred in the tests carried out 
at low temperatures, and not in those subjected to a temperature 
of 37 ° C. 
RELATION OF AUTO AGGLUTININ OF NORMAL BLOOD TO 
THAT PRESENT IN THE BLOOD OF ANIMALS 
INFECTED WITH TRYPANOSOMES 
In this connection it may be remarked that in the blood 
of infected animals there exists a considerable excess of 
auto-agglutinin beyond that present in the blood of normal animals. 
It was found that diluting the defibrinated plasma of normal blood 
with twice its volume of normal saline solution usually sufficed to 
estrov its agglutinating action. On the other hand, it was often 
possible to dilute the infected plasma 15- or 20-fold, and still 
otain complete agglutination of the erythrocyte suspension. 
EFFECT of HEAT on AUTO AGGLUTININ 
Different portions of the defibrinated plasma of normal and 
injected animals were heated in a water bath to 58° C. and J0° to 
I ' res P ectl 'ely for twenty minutes. Heating to 58° C. was 
not to destrov auto-agglutinin, whereas plasma which had 
^een su jected to a temperature of ;o c C. for twenty minutes had 
completely lost this property. 
