BY DR. LAUDER BRUNTON. 453 



possible. Collect the precipitate on a filter, and keep it for after 

 examination. . ...... (a) 



63. Creatine. Precipitate any lead present in the filtrate 

 by hydrogen sulphide: filter; evaporate the filtrate to a thin 

 syrup on the water-bath. Put it in a cool place for several 

 days, and the creatine will separate in short colorless crystals. 

 Let it stand till no more crystals are deposited; pour oft' the 

 mother liquor from the ciystals, and add to it two or three times 

 its volume of alcohol of 88 per cent., so as to cause the sus- 

 pended creatine to be deposited. Filter it, and wash the crys- 

 tals with a little alcohol. Wash off the crystals which still re- 

 main on the evaporating dish with the alcohol which drops 

 from the filter, throw them also on the filter, and wash them 

 with a little alcohol. Collect the filtrates, mix them and put 

 them aside. ......... (6) 



Dissolve the crystals in a little boiling water, and allow the 

 solution to cool, when the creatine will ciystallize out in color- 

 less transparent and lustrous oblique rhombic prisms, which, 

 when gently heated on a piece of platinum foil, lose water of 

 crystallization, and become dull and whitish. 



Solubility. Creatine is sparingly soluble in cold water ; 

 easily soluble in boiling water ; almost insoluble in strong alco- 

 hol; insoluble in ether. 



Reaction. The solution in hot water has a neutral reaction, 

 and bitter taste. 



Test. Creatine has no very characteristic reactions, and it 

 is best recognized by converting it into creatinine. If it is 

 pure, no precipitate will fall on the addition of zinc chloride to 

 its solutions, but if mixed with creatinine a precipitate will be 

 produced. 



Decomposition. When it is boiled for a considerable time 

 with caustic baryta, creatinine decomposes into urea and sar- 

 cosin. If the boiling is continued still longer, the urea decom- 

 poses into carbonic acid and ammonia. This reaction is very 

 interesting as indicating one source of urea in the body. When 

 boiled with water for a long time or with acids, it loses water 

 and is converted into creatinine. 



64. Creatinine. Boil creatine for half an hour with dilute 

 hydrochloric acid ; neutralize with hydrated lead oxide ; filter ; 

 evaporate the filtrate to dryness on the water-bath. Extract 

 the residue with alcohol, and evaporate the extract. The crea- 

 tinine will crystallize in colorless lustrous prisms, which, when 

 heated on platinum foil, do not dry like creatine. 



Solubility. It is soluble in water, especially when hot. Un- 

 like creatine, it is soluble in hot alcohol. 



Reaction. Test the watery solution with litmus or turmeric 

 paper ; it will be found strongly alkaline. It has a taste like 

 dilute ammonia. 



