312 LEO LOEB. 



a single row and may form one long continuous thread passing 

 over a large part of the slide. 



Sometimes very little effort is needed to achieve such a trans- 

 formation. If we move the solution containing a few drops of 

 blood in one direction the flow of the liquid may be sufficient to 

 arrange the cells into rows and draw them out into continuous, 

 long threads. 



Such fibrils are, however, not only formed from the protoplasm 

 of the entire cell but they also may be formed inside of cells. 

 This can be observed, for instance, if we exert traction by a 

 needle in a network of cells spread out on the slide, c. g., about 

 half an hour after the blood has been shed. If we merely exert 

 pressure on masses of cells we may change them into a structure- 

 less gelatinous mass* By exerting afterwards traction on such a 

 gelatinous mass, using two slides, we can change this mass into a 

 system of fibrils of different diameters ; such fibrils can again be 

 rolled up into a gelatinous mass. The protoplasm has in this 

 case the consistency of a dough, differing however in that it is 

 somewhat more elastic. 



If we apply these mechanical agencies to cells immediately 

 after they have left the body, we find the protoplasm more brittle 

 and the cells can under these conditions by pressure easily be 

 separated into small granular particles. 



A transformation into fibrils can al,so be produced from the 

 protoplasm which ha'd previously left the body of the ruptured cell, 

 or from the protoplasm of exploded cells. The same agencies, 

 traction and pressure, are also able to make the granules of the 

 cells disappear. Cells which had been previously kept for a 

 longer period in saturated salt solutions or in formalin, no longer 

 yielded such a fibrillar mass. ^ 



The physical properties of this fibrin-like mass are very similar 

 to the fibrin formed through the coagulation of the extra-cellular 

 part of the blood. The cellular fibrin can be drawn out, and as 

 it is somewhat elastic, may afterwards slowly retract. It is also 

 sticky. The cells themselves have similar physical properties. 

 If they are spread out, as is usually the case, one half to one 

 hour after coagulation they are kept under great tension, and if 

 liberated from the surface of the slide by a needle they retract. 



