442 PRACTICAL ORGANIC AND BIO-CHEMISTRY 



(c) Oxalate Plasma. 



On diluting with 5 volumes of water, no clotting occurs at 40. 

 Clotting occurs on diluting and adding a few drops of calcium chloride 

 and warming to 40. 



On diluting and adding a drop of serum, freed from calcium salts 

 by precipitation with oxalate, and warming to 40, clotting occurs. 



This plasma contains fibrinogen, but the formation of thrombin 

 has been prevented by the absence of calcium salts. On their addi- 

 tion thrombin is formed and clotting takes place. 



Serum contains thrombin, and hence, when added free from cal- 

 cium salts to plasma free from calcium salts, clotting occurs. Calcium 

 salts are therefore necessary for the formation of thrombin. 



(d) Fluoride Plasma. 



On diluting with 2 volumes of water, it does not clot on warm- 

 ing to 40. 



No clotting occurs on diluting and adding a few drops of calcium 

 chloride and warming to 40. 



Clotting occurs on diluting and adding a drop of serum or throm- 

 bin solution. 



Clotting occurs on diluting and adding a scraping of muscle or 

 other tissue. 



These results are only obtained if the plasma has been thoroughly 

 centrifugalised ; if improperly centrifugalised, corpuscles will be present 

 which yield thrombokinase. 



The plasma contains fibrinogen and thrombogen, but no throm- 

 bokinase. Thrombin cannot be formed in the absence of throm- 

 bokinase when calcium salts are added. 



Composition of Blood. 



Blood plasma consists mainly of water ; the solid matter amounts 

 to less than 10 per cent. The proportions of the constituents have 

 been frequently determined and some of the analyses for 1000 c.c. are 

 given in the following tables : 



Horse. Man and other Chicken. Frog. 



, x Animals. 



Hoppe Seyler. Hammarsten. 

 Water .... 908-4 917-6 



Solids .... 91-6 82-4 70 to 97 54 



1000*0 1000*0 



Fibrin .... ro'i 6*5 



Globulin . . . 38-4 



Albumin . . . 24-6 



Total Proteins . 55 to 84 39-5 25-4 



Fat 1-21 



Extractives ... 4 -o I 



Soluble Salts . . . . 6- 4 j T 3'3 

 Insoluble Salts . . .1-77 



