ACTION OF REAGENTS ON RED CORPUSCLES. 227 



These changes are checked by cold, and facilitated by heat, a 

 temperature above that of the body causing them to take place 

 almost immediately. Associated with the loss of function of the 

 disks is observed a change accompanied by an apparent increase 

 of adhesiveness, which causes them to stick together, commonly 

 adhering by their flat surfaces, so as to form into rolls, like so 

 many coins placed side by side. That this adhesion is not a mere 

 physical process, independent of the chemical properties of the 

 corpuscles themselves, seems proved by the following facts: (1) 

 It does not occur immediately when the blood is drawn, and it 

 disappears after a certain time without the addition of reagents; 

 (2) while the blood is in the living vessels under normal condi- 

 tions there is no adhesion, but it soon appears when any stand- 

 still in the circulation takes place as in inflammation; (3) it 



FIG. 100. FIG. 101. 



I 



FIG. 100. Microscopic appearance of the blood after the addition of 

 distilled water. Red Corpuscles become colorless or pale, separate, and 

 spherical. The white are seen to be swollen round and granular, with clear 

 nuclei. 



FIG. 101. Showing effect of evaporation. Six Red Corpuscles crenated. 

 (w) White cellchanging shape. 



does not occur when saline solutions are added to the blood. It 

 seems then to be dependent upon a peculiar property of the disks, 

 which only exists for a time coincident with the changes that 

 accompany the appearance of fibrin. 



The shape of the disks changes when the density of the medium 

 in which they are suspended is altered. When the density is 

 reduced, as by the addition of water, they swell and become 

 spherical, and break up the rouleaux, the coloring-matter at the 

 same time becoming dissolved in the medium. (Fig. 100.) When 



