Page:The third Huxley lecture.pdf/20

16 well as individual leucocytes adhering to the surface of the glass, along which, as has been since observed,, they crawl by amoeboid movements.

In the red corpuscles the tendency to mutual adhesion shows itself in different forms according to the species of the animal or its state of health. In the frog the prominence of the nuclei leads to very irregular grouping of the oval cells. In man the biconcave circular discs adhere under normal circumstances in that position which enables their moderate degree of adhesiveness to come best into play, the result being the well-known "rouleaux." The same is seen in the healthy blood of the cow. But in some animals, e.g., the horse, the adhesiveness of the discs is so great that they stick to one another by the parts that come first into contact, producing dense spherical masses large enough to be visible to the naked eye, like grains of red sand. These, falling rapidly through the lighter plasma, leave the upper part of the liquid free from red corpuscles before coagulation occurs, thus giving rise to the huffy coat, whereas in the cow the delicate network of rouleaux remains suspended, and no buff occurs.

I am greatly surprised to learn that the cause of the huffy coat is stated in some text-books to be slowness of coagulation. Special slowness of coagulation does not occur in buffing blood; nor, if it did, would it explain the phenomenon. In whipped horse's blood the red discs aggregate into dense masses as in blood freshly drawn, and falling rapidly soon