426 BLOOD AND LYMPH. 



SERUM- 

 TOTAL PROTEINS. ALBUMIN. PARAGLOBULIN. FIBRINOGEN. 



Man 7.26 4.01 2.83 0.42 



Dog 6.03 3.17 2.26 0.60 



Sheep 7.29 3.83 3.00 0.46 



Horse 8.04 2.80 4.79 0.45 



Pig 8.05 4.42 2.98 0.65 



Other Proteins of the Blood-serum or Blood-plasma. From time to time 

 other protein bodies have been described in the serum or plasma of the blood. 

 In the serum after coagulation Hammarsten has obtained a globulin body, 

 fibrin-globulin, which he supposes may be split off from the fibrinogen during 

 the act of clotting. Faust, as was mentioned above, describes an albuminoid 

 substance, glutolin, which is present in the blood and is usually precipitated 

 together with the paraglobulin. A number of observers have noted the ex- 

 istence in blood of a protein not coagulated by heat. By some authors this 

 has been described as a peptone or an albumose (Langstein), by others as an 

 ovomucoid (Zanetti), and by others still (Chabrie) as a peculiar protein for 

 which the name albumon has been proposed. By others still this non-coagu- 

 lable protein obtained from serum or plasma has been explained as an artificial 

 product arising from the globulins of the blood during the process of remov- 

 ing the coagulable proteins by heating. So, too, nucleoprotein substances 

 have been described in the blood-serum by several observers, most recently by 

 Freund and Joachim. It is quite possible, however, that the substance de- 

 scribed as nucleoprotein is in reality a mixture or combination of lecithin and 

 protein. Most of the protein when precipitated from the blood carries down 

 with it some lecithin, and will therefore show a reaction for phosphorus. It 

 can be shown that the phosphorus present is, in most cases at least, remov- 

 able by boiling with alcohol, and there is at present no entirely satisfactory 

 proof that nucleoprotein exists in the blood. 



Coagulation of Blood. One of the most striking properties of 

 blood is its power of clotting or coagulating shortly after it escapes 

 from the blood-vessels. The general changes in the blood during 

 this process are easily followed. At first perfectly fluid, in a few 

 minutes it becomes viscous and then sets into a soft jelly which 

 quickly becomes firmer, so that the vessel containing it may be 

 inverted without spilling the blood. The clot continues to grow 

 more compact and gradually shrinks in volume, pressing out a 

 smaller or larger quantity of a clear, faintly yellow liquid to which 

 the name blood-serum is given. The essential part of the clot is the 

 fibrin. Fibrin is an insoluble protein not found in normal blood. 

 In shed blood, and under certain conditions in blood while still in the 

 blood-vessels, this fibrin is formed from the soluble fibrinogen. 

 The deposition of the fibrin is peculiar. It is precipitated, if the 

 word may be used, in the form of an exceedingly fine network of 

 delicate threads that permeate the whole mass of the blood and give 

 the clot its jelly-like character. The shrinking of the threads 

 causes the subsequent contraction of the clot. If the blood has not 

 been disturbed during the act of clotting, the red corpuscles are 

 caught in the fine fibrin meshwork, and as the clot shrinks these 

 corpuscles are held more firmly, only the clear liquid of the blood 

 being squeezed out, so that it is possible to get specimens of serum 

 containing few or no red corpuscles. The leucocytes, on the con- 



