HANDBOOK FOE BIO-CHEMICAL LABOBATOBY. 53 



Creatin, 



C 4 H 9 N 3 O a + H 2 or NH. : C [NHJ.N[CH 3 ].CH 2 .COOH. 

 Syn. METHYL GUAKIDIH ACETIC ACID. 



Preparation. 1. Beef extract (Liebig's) is treated with 

 water and the albumin removed as far as possible by heating 

 to boiling, and filtering. The filtrate is precipitated by the 

 careful addition of basic lead acetate, taking care not to add 

 too great an excess of the precipitant. Filter, remove the 

 excess of lead acetate in the filtrate by H a S, and evaporate the 

 nitrate to a small volume at moderate temperature. Allow 

 the solution to stand one week in a cool place, filter off the 

 separated crystals, wash with 88$ alcohol, and purify when 

 necessary by recrystallization. The crystals may be decoloF- 

 ized by dissolving them in hot water to which animal charcoal 

 has been added, filtering,and allowing the filtrate to crystallize. 



2. Finely chopped meat is mixed with one half its weight 

 of water, pressed, and the residue again extracted with the 

 same amount of water. This extract is freed from albumin 

 by heating to boiling and filtering, and adding a solution of 

 baryta water to the filtrate as long as a precipitate forms. 

 Filter off the precipitated phosphates, remove the excess of 

 baryta by means of carbon dioxide, filter, and evaporate the 

 filtrate to one twentieth of its volume on the water-bath. The 

 syrup is allowed to stand several days in a cool place when 

 crystals will form. If a skin should form on the surface this 

 should be removed. 



3. Chopped meat is treated with ether and allowed to stand 

 for a few days, when a strongly acid fluid separates out. This 

 is colored red, due to myoheematin. This watery fluid is sep- 

 arated and evaporated, when crystals of creatin will separate 

 out, which may be purified by recrystallization as above. 

 (MacMunn.) 



Properties. Creatin crystallizes in hard, colorless, shining, 



