FIBRIN. 247 



perature, or much more readily at 40 C., and this solution takes place, 

 according to ARTHUS and HUBERT and also DASTRE/ without the aid 

 of micro-organisms. This action is due to proteolytic enzymes carried 

 down by the fibrin or enclosed within the leucocytes (RULOT 2 ) . Accord- 

 fng to GREEN and DASTRE 3 two globulins are formed in the solution 

 of fibrin in neutral salt solution, and according to RULOT also proteoses 

 (and peptones) on the solution of fibrin containing leucocytes. Fibrin, 

 like fibrinogen, decomposes hydrogen peroxide, due to a contamination 

 with catalases, but this property is destroyed by heating or by the action 

 of alcohol. 



What has been said of the solubility of fibrin relates only to the typical 

 fibrin obtained from the arterial blood of oxen or man by whipping 

 and washing first with water and with common salt solution, and then 

 with water again. The blood of various kinds of animals yields fibrin 

 with somewhat different properties, and according to FERMI 4 pig-fibrin 

 dissolves much more readily than ox-fibrin in hydrochloric acid of 5 p. m. 

 Fibrins of varying purity or originating from blood from different parts 

 of the body have unlike solubilities. 



The fibrin obtained by beating the blood, and purified as above de- 

 scribed, is always contaminated by secluded blood-corpuscles or remains 

 thereof, and also by lymphoid cells. It can be obtained pure only from 

 filtered plasma or filtered transudates. For the preparation of pure fibrin, 

 as well as for the quantitative estimation of it, the spontaneously coagu- 

 lating liquid is at once, or the non-spontaneously coagulating liquid only 

 after the addition of blood-serum or fibrin ferment, thoroughly beaten 

 with a whalebone, and the separated coagulum is washed first in water 

 and then with a 5-per cent common salt solution, and again with water, 

 and finally extracted with alcohol and ether. If the fibrin is allowed to 

 stand for some time in contact with the blood from which it was formed, 

 it partly dissolves (fibrinolysis DASTRE 5 ) . This fibrinolysis must be 

 prevented in the exact quantitative estimation of fibrin (DASTRE). The 

 blood constituents that are active in fibrinolysis are still unknown, but 

 they are without doubt of enzymotic nature. It must be mentioned that 

 a strong fibrinolysis takes place in blood after acute phosphorus-poisoning 

 (JACOB Y and others), after extirpation of the liver (Now), and also when 

 the coagulability of the blood has been reduced by the injection of pro- 

 teoses (NoLF, RULOT 6 ) . 



A pure fibrinogen solution may be kept at the ordinary temperature 

 until putrefaction begins without showing a trace of fibrin coagula- 



1 Arthus and Hubert, Arch, de Physiol. (5), 5; Dastre, ibid., (5) 7. 



2 Arch, intern, de Physiol., 1. 



3 Green, Journ. of Physiol., 8; Dastre, 1. c. 



4 Zeitschr. f. Biologic, 28. 



5 Archives de Physiol. (5), 5 and 6. 



6 Jacoby, Zeitschr. f. physiol. Chem., 30; Tolf, Arch, intern, de Physiol., 3, 1905; 

 Rulot, 1. c. 



