3O2 LEO LOEB. 



1. The Agglutination of Blood Corpuscles. This phenomenon 

 may be observed uncomplicated by the other factors, c. g., if we 

 collect blood in distilled water, in solutions of gelatine or of ad- 

 renalin. Under these conditions the cytoplasm of the cells itself 

 furnishes a sticky substance necessary for agglutination. Coag- 

 ulation of the blood of arthropods is partially based on the ag- 

 glutination of the blood cells taking place spontaneously outside of 

 the body. 



2. Just as the cells agglutinate, so the cell protoplasm having 

 left the ruptured cell body agglutinates, and the remaining part 

 of the cell frequently has the appearance of still intact but smaller 

 cells. The protoplasm of cells which have been absolutely dis- 

 solved may also agglutinate and form gelatinous masses. 



3. About six to ten minutes after the shedding of the blood 

 the blood cells, which in the meantime have been mostly col- 

 lected in strings, begin to move in contact with solid bodies, e. g., 

 the surface of the slide ; the protoplasm of the cell becomes more 

 and more drawn out, so that ultimately a fine network of flattened 

 cells is formed in which for a certain time the anastomosing 

 exoplasm can be distinguished from the granular endoplasm. 



4. There also takes place the coagulation of a substance which 

 previously was in solution. This coagulation is especially marked 

 in the blood of the lobster, but it also takes place to a less degree 

 in the blood of Liimdus. 



II. ON SOME OF THE FACTORS DETERMINING THE SECOND 

 COAGULATION OF THE BLOOD OF THE LOBSTER. 



The conditions under which the coagulation of the substance 

 first in solution in the blood of arthropods takes place can best 

 be studied in the blood of the lobster. If, after the shedding of 

 the blood, one quickly collects the first fibrin by shaking the 

 vessel and then removing it with needles, the coagulation can be 

 inhibited for longer or shorter periods, or even be entirely pre- 

 vented. The fact that coagulation nevertheless usually takes 

 place, although somewhat later, is partially to be explained by 

 the fact that it is impossible to remove all shreds. These shreds 

 mostly consist of agglutinated cells. If one examines the second 

 gelatinous coagula formed at the bottom of the dish, even after 



