72 CHEMICAL CONSTITUTION OF BLOOD-PLASMA AND SERUM. 



production of fibrin, Landois was able in 1874 to follow directly under 

 the microscope the transformation of the stromata of the red blood-cor- 

 puscles of mammals into fibrin-fibers. If a drop of defibrinated rabbit's 

 blood be introduced into frog's serum, without agitation, it will be 

 observed that the erythrocytes attach themselves to one another. They 

 become viscous upon the surface, and on pressure on the cover-slip it 

 will be seen the adhesion can be broken up only with a certain amount 

 of force, the adjoining surfaces of the swollen, globular corpuscles often 

 being drawn out into threads. Even after the process has been in 

 operation for a short time, all of the corpuscles are transformed into 

 globules of lesser diameter and those lying nearest the periphery permit 

 their hemoglobin to escape. The decolorization progresses from the 

 periphery of the drop to the center, and finally only a coherent mass of 

 stroma remains. The substance of the stroma exhibits great tenacity. 

 At first the round contours of the individual blood-corpuscles can still 

 be recognized, but as soon as a current is set up in the surrounding fluid 

 by pressure upon or movement of the cover-glass, the stroma-mass 

 becomes agitated to and fro and the stromata lying close together and 

 adherent to one another become drawn out into delicate filaments and 

 bands, with simultaneous disappearance of the previous contour of 

 the cells. In this way the formation of fibrin-filaments from the stro- 

 mata of the red blood-corpuscles can be followed step by step. Erythro- 

 cytes from human beings and from animals undergoing dissolution in 

 the serum of different animals often exhibit the same phenomena. 



Stroma-fibrin can be prepared also in the following simple manner: A one 

 per cent, solution of sodium chlorid is shaken in a reagent-glass with ether and 

 a few drops of defibrinated blood. The mixture soon becomes lake-colored. 

 Put aside, the ether, which rises to the tpp, carries with it the filamentous stroma- 

 fibrin to the surface of the fluid. 



Stroma-fibrin and Plasma-fibrin. Landois has designated stroma- 

 fibrin that which arises directly from the stroma of the erythrocytes. 

 On the other hand, the fibrin that is produced through the combination 

 of the fibrin-factors dissolved in the coagulating fluid plasma is 

 plasma- fibrin, or ordinary fibrin. Both designations are fully justified, 

 if only to indicate the mode of origin of the fibrinous mass. 



Substances that cause rapid dissolution of the erythrocytes bring 

 about extensive coagulation, as, for instance, injection of bile or salts 

 of the biliary acids, or of lake-colored blood into the veins. The 

 effective agent under these circumstances is the stroma, through the 

 development of the ferment, and in lesser degree the hemoglobin. As 

 foreign blood after injection often undergoes rapid disintegration in the 

 blood-stream of the recipient, extensive coagulation is often observed 

 under such circumstances, while at the same time the individual 

 smaller vessels are often occluded by plugs of stroma-fibrin . 



CHEMICAL CONSTITUTION OF THE BLOOD-PLASMA AND THE 



SERUM. 



The proteids constitute about 8 or 10 per cent, of the plasma. Of 

 these only about 0.2 per cent, are bodies producing fibrin. If these be 

 eliminated through the process of coagulation, the plasma is trans- 

 formed into serum. The specific gravity of human serum is between 1027 

 and 1029. The blood-plasma contains, besides, the following proteids: 



