Crassamentum

Though air is excluded from venous blood the instant it is drawn, as by receiving it in fresh white of egg, milk or serum, in which it immediately sinks, nevertheless on coagulation the surface of the crassamentum will be of a comparatively light florid hue.

If healthy blood be allowed to remain at rest, it separates into two parts, a red solid portion called crassamentum, and a thin watery part or serum.[…]This shows that the proportion of fibrin in the crassamentum does not vary rapidly.

Such as are the volumes, such are the crassamenta belonging to the volumes, and such also are the masses ; that is to say, if the volumes are pure, mixed homogeneous, or mixed heterogeneous, such respectively are the crassamenta and the masses.