246 Dr. W. Yorke. <Auto-Agglutination of [Nov. 2, 
at higher temperatures (37° to 40° C.), the question arises as to whether 
the absorption of agglutinin belongs to the group of reactions which have 
been designated “reversible.”* In other words, will raising the temperature 
of the agglutinated masses of red cells cause the clumps to disintegrate into 
their corpuscular elements ? 
Experiment.—One volume of red corpuscles of Rabbit 1022 (infected with 
T. gambiense) was added to 20 volumes of the defibrinated plasma of the 
same animal. After an hour’s sojourn in the ice chest complete agglutina- 
tion of the erythrocytes was found to have occurred. After stirring the 
clumps up thoroughly with a glass rod a small drop of the suspension was 
placed on a cover-slip and a hanging drop preparation made. On examining 
with the microscope large masses of agglomerated red blood cells and also 
considerable rouleaux formation were seen. The mixture of clumped red 
cells and defibrinated plasma was now placed in the incubator at 37° C. 
In about 15 minutes the clumps were no longer visible, and the erythrocytes 
appeared to be evenly suspended throughout the fluid. A hanging drop 
preparation was made on a warm slide and cover-slip. As long as the 
temperature was maintained at 37° C., there was no tendency to agelutina- 
tion. When the suspension was again cooled to 0° C., agglutination of the 
red cells reappeared after a few minutes. 
From this and similar experiments it follows that the reaction is reversible, 
the phenomenon disappearing on warming and reappearing on cooling. 
Auto-agglutination in the Blood of Normal Animals.—Attention has already 
been drawn to the fact that a certain amount of auto-agglutination was 
frequently observed in the control tests of normal blood. Some years ago 
Kleint found auto-agglutinin to be present in the serum of a number of 
normal horses. 
Landsteinert demonstrated the existence of a similar substance in the 
blood of rabbits, horses, dogs, and cattle. 
Other writers, on the contrary, deny the existence of auto-agglutinin in 
normal blood. Dudgeon§ in a recent paper states that auto-agglutination 
does not occur in normal human blood. 
It was decided to re-investigate this subject more fully, using the blood of 
considerable number of normal animals of different kinds. 
* Arrhenius, ‘Immuno-Chemistry,’ ch. 2. 
+ ‘ Beitraige zur Kenntniss der Agglutination rother Blutkérperchen,” ‘Wien. Klin. 
Woch. 1902, No. 16, p. 413. 
t “Ueber Beziehungen zwischen dem Blutserum und den Kérperzellen,” ‘Miinch. Med. 
W och.,’ 1903, No. 42. 
§ “On the Presence of Hemagglutinins, etc., in the Blood obtained from Infectious 
and Non-Infectious Diseases in Man,” ‘Roy. Soc. Proc.,’ 1909, B, vol. 81, p. 207. 
