ALBUMEN: FIBRIN. 23 



while a stream of water flows upon it, the whole of 

 the blood-colour is gradually removed, and strings and 

 various pieces remain of a soft, yet tough, elastic, and 

 opaque-white substance, which consist of fibrin, impure, 

 with a mixture of fatty matter, lymph-corpuscles, shreds 

 of the membranes of red blood-corpuscles, and some 

 saline substances. Fibrin somewhat purer than this 

 may be obtained by stirring blood while it coagulates, 

 and collecting the shreds that attach .themselves to the 

 instrument, or by retarding the coagulation, and, while 

 the red blood- corpuscles sink, collecting the fibrin un- 

 mixed with them. But in neither of these cases is the 

 fibrin perfectly pure. 



Chemically, fibrin and albumen can scarcely be distin- 

 guished ; the only difference apparently being that fibrin 

 contains 1-5 more oxygen in every 100 parts than albumen 

 does. Nearly all the changes, produced by various agents, 

 in coagulated albumen, may be repeated with coagulated 

 fibrin, with no greater differences of result than may be 

 reasonably ascribed to the differences in the mechanical 

 properties of the two substances. Of such differences, the 

 principal are, that fibrin immersed in acetic acid swells up 

 and becomes transparent like gelatin, while albumen 

 undergoes no such apparent change ; and that deutoxyde 

 of hydrogen is decomposed when in contact with coagulated 

 fibrin, but not with albumen. 



The difference between albumen and fibrin being 

 thus so small, and due apparently to a slight increase in 

 the amount of oxygen in the latter, it occurred to 

 Mr. Alfred H. Smee that albumen might be converted 

 into fibrin if subjected to the prolonged influence of 

 oxygen. Having exposed completely defibrinated blood 

 to a stream of oxygen for about thirty-six hours, he 

 found at the end of that time that small masses were 

 formed, which possessed the general and microscopic 

 characters of fibrin. A similar formation of fibrin took 



