The study of the phenomena of agglutination has given us many new and interesting facts, and among others this one, that agglutination is not limited in its field of action to bacteria only, but that under certain circumstances the action is exercised on such elements as the red corpuscles of the blood. Indeed, the rouleaux-formation of the red discs is a kind of agglutination. The extent of rouleaux-formation varies under different conditions; at the present time it is almost wholly ignored as a factor in the production of the buffy coat in coagulation of the blood. But recent investigations by Shattock1 show that the agglutination of red blood-corpuscles stands in a more or less direct relation to certain substances in the serum, and that it probably merits more attention in human pathology than it is now accorded.
Shattock shows that in horse's blood rouleaux-formation is highly pronounced and it