ix FIBRINOGEN 379 



especially investigated by Arthus. 1 According to the latest statements 

 of Hammarsten, fibrinogen is preformed in the blood, and becomes 

 coagulated equally well whether present in the blood or after isolation 

 in a pure form. It is coagulated by a ferment which is derived from 

 the formed elements of the blood. The leucocytes or red corpuscles 

 do not, however, give rise to the ferment directly, but to its zymogen, 

 which is converted in the plasma into the active ferment. Space 

 forbids to enter more fully into the question of coagulation, and into 

 the question as to how pro-ferments are converted into ferments. 2 

 One fact, however, Hammarsten has definitely proved, namely, that 

 the fibrin-ferment, if once formed, is capable of converting fibrinogen 

 into fibrin, even in the absence of lime. Fibrin is neither a fibrinogen- 

 lime compound, nor has lime anything to do with fibrinogen or with 

 fibrin. The slight amounts of lime, namely, O'OOG per cent, which 

 Hammarsten found in preparations made from oxalate-plasma solu- 

 tions, are not specific for fibrin, but only correspond to the ash, which 

 is present also in other albumins. 



Fibrin-ferment has the properties of other ferments : it is active 

 in very small amounts ; Hammarsten prepared an exceedingly active 

 solution, which contained only 0'3 per 1000 of solid ingredients; it is 

 destroyed by heat, and also on being kept for some time in alcohol ; it 

 cannot, of course, be prepared in a pure state. Fibrin-ferment or sub- 

 stances which call forth the coagulation of blood, or at least hasten it, and 

 which cause clotting even in the circulating blood, have been found by 

 Alexander Schmidt and by Wooldridge 3 in all organs rich in cells. 



On the other hand, leeches, crab-muscle, and other bodies contain 

 substances which enormously retard coagulation on being introduced 

 into the circulation. Pick and Spiro 4 found a body giving analogous 

 reactions in the digestive organs, namely, the "peptozyme." This 

 enzyme, by attaching itself to the albumoses and peptones formed 

 during digestion, is the real cause which prevents the coagulation of 

 blood if albumoses, Witte's peptone, and other peptone-preparations 

 are injected into the circulation. This anti-coagulative property of 

 the products of digestion was discovered by Schmidt-Muhlheim 5 and 



1 M. Arthus and C. Pages, Arch, de Physiol. normale et pathologique, 1890, p. 739 ; 

 M. Arthus, ibid. 1894, p. 552 ; 1896, p. 47 ; and These, 1890. Good account of litera- 

 ture. See also Gompt. rend. Soc. Biol. 53. 962 and 3024 (1901). A very complete 

 account of the literature is given by Lilienfeld, Zeitschr. f. physiol. Ohem. 20. 89 (1894). 



2 P. Morawitz, Hofmeister's Beitrage, 4. 381 (1903) ; Deutsch. Arch. f. Tdin. Med. 

 79. 1 (1903); and Hofmeisters Beitrage, 5. 133 (1904); E. Fuld and K.. Spiro, 

 ibid. 5. 171 (1904). 



3 L. C. Wooldridge, Archiv. f. (Anat, u.) Physiol. 1886, p. 397. 



4 E. P. Pick and K. Spiro, Zeitschr. f. physiol. Chem. 31. 235 (1900). 



5 A. Schmidt-Miilheim, Archiv f. (Anat.u.) Physiol. 1880, p. 33. 



