34 PKOTEIDS. 



The possible solubility of fibrin under certain conditions in saline 

 solutions of moderate strength obtained considerable importance 

 in the controversy between Schmidt and Hammarsten as to the 

 nature of the processes involved in the clotting of blood. When 

 on the other hand fibrin is subjected to the prolonged action 

 of more concentrated (10 p.c.) solutions of neutral salts, and 

 the salt solution is frequently renewed, the fibrin may be finally 

 completely dissolved, being converted into members of the glob- 

 ulin class. 1 Most observers agree that the globulin thus chiefly 

 formed coagulates at 55 56. Green obtained in addition one 

 coagulating at 59 60, the two differing further in their solubili- 

 ties in 1 and 10 p.c. solutions of NaCl. These changes are 

 brought about by the salts in the entire absence of any putre- 

 factive phenomena, and the resulting globulins cannot be made 

 to yield fibrin again by any treatment with fibrin-ferment. 



When fresh unboiled fibrin is simply washed till it is white 

 and digested with pure active trypsin, it is largely converted 

 into coagulable proteids during the initial stages of the ferment 

 action. 2 These proteids are characteristically globulins and one 

 is closely related to paraglobulin, as judged of by its coagulating 

 in saline solutions at 75 and possessing a specific rotatory power 

 (in 10 p.c. NaCl) of (o),>=-481 . 3 The second globulin pro- 

 duct of the ferment action coagulates at 55 56, and in this 

 respect more closely resembles fibrinogen. 4 Whether the whole 

 of the globulin thus obtained is a product of the conversion of 

 the fibrin, or whether a portion of it is due to globulin existing as 

 such in the raw fibrin, is not yet stated. Similar globulins are 

 produced by the action of pepsin in its earlier stages on raw 

 fibrin. If the fibrin is boiled or treated for some time with al- 

 cohol before digestion with either of the above enzymes, mere 

 traces, if any, of these globulins are obtained. 



The purest fibrin always leaves a small but fairly constant ash- 

 residue on incineration. Of the inorganic constituents of winch 

 this residue is composed it is probable that sulphur is the only 

 element which enters essentially into the composition of the 

 fibrin. 



When boiled in water or treated for some, time with alcohol it 

 loses its elasticity, becomes much more opaque, is much less 

 soluble in the various reagents which dissolve the original fibrin 

 with comparative ease, is attacked with much greater difficulty 



1 Green, .//. ofPki/siol. Vol. vin. (1887), p. 373. Limbourg, Zt. / phi/siol. Chem 

 Bd xin. (1889), S. 450. The latter contains a complete list of references to the 

 literature of the subject excepting Pldsz, Pfliiger's Arch. Bd. vn. (1873), S. 382. 



2 Briicke, Wien. Sitzber. Bd. xxxvii. (1859), S. 131. Kiihne, Virchow's Arch. Bd. 

 xxxix. (1867), S. 130. Lehrbuch, S. 118. Kistiakowsky, Pfluger's Arch. Bd. ix. 

 (1874), S. 446. 



3 Otto, Zt. f. physiol. Chem. Bd. vm. (1883), S. 130. 



4 Hasebroek, Zt. f. physio/. Chem. Bd. xi. (1887), S. 348. Herrmann, Ibid. S. 

 508. But see Neumeistef, Zt. f. Biol. Bd, xxm. (1887), S. 398. Salkowski, Ibtd. 

 Bd xxv. (1889), S. 97. 



