XIV.] 



MUSCLE. 



lOI 



5. The Extractives of Muscle. — Prepare Kreatin (C4HyN302 + H20) 

 omitting the others. 



(a.) Make a strong watery solution of Liebig's extract of moat. Cautiously 

 add lead acetate until precipitation ceases, avoiding excess of the lead. Filter, 

 pass sulphuretted hydrogen through 

 the filtrate to get rid of the lead. 

 A pellicle is very apt to form on the 

 surface. Filter, and evaporate the 

 filtrate to a syrup on a water-bath, 

 and set it aside in a cool place to 

 crystallise. Crystals of kreatiii 

 separate out. 



(b.) After several days, when 

 the kreatin has separated, pour 

 off the mother-liquor, add to it 5 



volumes of 90 per cent, alcohol to precipitate more kreatin. Filter, wash 

 the crystals with alcohol, redissolve them in boiling water, allow them to 

 recrystallise, and examine them with the microscope (fig. 51). 



Sarkin and xanthin may be prepared from the alcoholic filtrate of (/;.). 



The following scheme after Salkowski shows the process of making 

 it from flesh. 



Preparation of Kreatin. 



Minced flesh, digested with water, strained. 



FlO. 51.— Crystals of Kreatin. 



Filtrate heated to 

 boiling, filter. 



Residue. 



Filtrate + lead acetate 

 filter. 



Residue = coagulated 

 albumin. 



Filtrate + HgS to remove 

 lead, filtrate concentrated 



= Kreatin. 



Deposit = phosjjhate 



chloride and sulphate 



of lead. 



test. 



6. Liebig's Extract of Meat. 



{a.) Test it for proteids ; they are absent. 



{h.) Test it for glycogen, doing a control 

 tains a small quantity. 



(c.) Test it for kreatinin (see "Urine"), 

 succeeds. 



{(l.) Examine it microscopically ; in addition to a few crystals 

 of common salt, a few clear knife-rest forms, there are numerous 

 crystals of kreatin. 



It usually con- 

 Weyl's test usually 



