FIBRINE OF BLOOD. 117 



drawn blood with a bundle of twigs. Remove the 

 fibrine adhering to the twigs, put it in a bag, tie the 

 mouth of the bag tightly round a tap, and allow water 

 to run through, frequently kneading the mass, until 

 colourless. The substance thus obtained is fibrine 

 mixed with white blood-corpuscles. 



2. Keep moist fibrine in a covered beaker in a 

 warm place. It will gradually liquefy and give off 

 an offensive smell, owing mainly to butyrate and 

 valerate of ammonia. The mass mixed with water 

 will coagulate on heating, showing the presence of 

 albumen. Ammonium sulphide will also be formed, 

 and will blacken a slip of paper moistened with lead 

 acetate. 



3. Extract with boiling water, evaporate to dryness, 

 and digest with strong alcohol. Evaporate the 

 alcohol solution to dryness ; the residue will give the 

 reactions of leucine (q.v.). The portion insoluble in 

 alcohol must be treated with a little concentrated 

 hydrochloric acid, and the acid solution precipitated 

 by excess of strong sodium acetate solution. The 

 precipitate will give the reactions of tyrosine (q.v.). 



4. Dry a portion and heat on platinum foil. It 

 takes fire, giving out a smell of burnt feathers, and 

 leaves a porous charcoal. 



5. Dissolve fibrine in dilute caustic potash at 60 C., 

 filter, and add slowly acetic or tribasic phosphoric 

 acid. A precipitate will be formed, soluble in excess 

 of acid. 



6. Boil with caustic potash, ammonia will be 

 evolved. Potassium sulphide will be formed in the 



