Well marked agglutination was frequently observed when the 
plasma obtained in this manner was added to a 5 per cent, 
suspension of red cells, whilst either a negative or only slightly 
positive result was obtained with the serum derived from blood 
which had clotted at laboratory temperature or in the ice chest. 
REVERSIBILITY OF THE REACTION 
In \iew oJ the tact that red cells absorb agglutinin to a much 
greater extent at low temperatures and only slightly at higher 
temperatures (37 0 to 40- C.), the question arises as to whether the 
absorption ol agglutinin belongs to the group of reactions which 
have been designated ' reversible.’ In other words, will raising the 
temperature ol 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 twenty volumes of the 
defibrinated plasma of the same animal. After an hour’s sojourn 
in the ilc chest complete agglutination of the erythrocytes was 
found to have occurred. After stirring the clumps up thoroughly 
with a glass lod a small drop of the suspension was placed on a 
i‘>\ei slip and a hanging drop preparation made. On examining 
with the microscope large masses of agglomerated red blood cells 
an also considerable rouleaux formation were seen. The mixture 
< umped led cells and defibrinated plasma was now placed in the 
• at ° r , a * 37 C. In about fifteen minutes the clumps were no 
gei \ isible, and the erythrocytes appeared to be evenly suspended 
ug out the fluid. A hanging drop preparation was made on 
^ arm anCl cover_s ^P- As long as the temperature was 
aine at ,7 C. there w r as no tendency to agglutination. When 
f, SUSpenS, ° n vvas a S a,n co °led to o° C. agglutination of the red 
‘-ells reappeared after a few minutes. 
is and Similar ex P eri ments it follows that the reaction 
rean^ erS13 e ’ ^ P ,lenomenon disappearing on warming and 
reappearing on cooling. 
lmmuno-Chemi.tr)-, ch. a. 
