THE CIRCULATING LIQUIDS OF THE BODY 41 



is artificially circulated through an excised liver, a substance 

 (perhaps an antithrombin) is formed which is capable of sus- 

 pending the coagulation of blood outside of the body, a property 

 which proteoses themselves do not possess, or possess only in 

 slight degree. It is not believed that the proteose is actually 

 changed into this anticoagulant substance, but rather that the 

 liver cells produce it as a ' reaction ' to the presence of the foreign 

 substance, being perhaps stimulated in some way by the cir- 

 culating proteose. In part the abnormally great alkalinity of 

 the peptone blood, due to the excess of alkali secreted by the 

 liver, is responsible for its slow coagulation. Under certain con- 

 ditions, some of which are known and others not, the injection 

 even of one or other of the purified proteoses causes not retarda- 

 tion, but hastening, of coagulation ; and if this has been the 

 result of a first injection, a second is equally unsuccessful. It 

 is possible that by an effort of the organism to restore the 

 normal coagulability of the blood, on which its very existence 

 depends, substances which favour coagulation are produced, and 

 that the result of an injection of proteose is determined by the 

 relative amount of coagulant and anticoagulant secreted in a 

 given time. Protamins (products obtained from the ripe milt of 

 certain fishes, and believed to be the simplest proteins) exert, 

 when injected intravenously, a retarding influence on coagula- 

 tion, and lower the blood-pressure, just as albumoses do (Thomp- 

 son). Even serum - albumin and serum - globulin possess this 

 property in some degree. All these substances also cause a 

 diminution in the number of leucocytes in the blood owing, in 

 the case of albumose at any rate, to their accumulation in the 

 abdominal vessels, and not to any actual destruction of them. 



The Chemical Composition of Blood. 



The serum of coagulated blood represents the plasma minus 

 fibrinogen ; the clot represents the corpuscles plus fibrin. Thus : 



Plasma Fibrin (ogen) = Serum. 



Corpuscles+ Fibrin=Clot. 



Plasma+ Corpuscles =Serum+ Clot= Blood. 



Bulky as the clot is, the quantity of fibrin is trifling (o - 2 to 0-4 per 

 cent, in human blood). The plasma contains about 10 per cent, 

 of solids, the red corpuscles about 40 per cent., the entire blood 

 about 20 per cent. 



Serum contains 8 to 9 per cent, of proteins, about o - 8 per cent, 

 of inorganic salts, and small quantities of neutral fats, soaps, 

 cholesterin esters, lecithin, urea, kreatin, dextrose, lactic acid, 

 and other substances. The chief proteins are serum-albumin and 

 serum-globulin. In the rabbit the former, in the horse the latter, 



