EXAMINATION OF MUSCULAR TISSUE. 31 



tated basic zinc carbonate, filter, evaporate to crystallization 

 (examine microscopically), and when this has begun add 

 alcohol. The zinc salt resulting is filtered off and freed 

 from the mother-liquor c'inging to it by pressing between 

 filter-paper. If it is quite free from sulphuric acid x (after 



FIG. 2. Zinc Sarcolactate. 



purification by recrystallization) make a determination of 

 the amount of the water of crystallization. For this purpose 

 weigh off on a watch-glass exactly 0.3 to 0.5 g. of the air-dried 

 zinc salt, and heat for some time in an air-bath at 115 until 

 the weight is constant. Zinc sarcolactate crystallizes with 

 two molecules of water, (C 3 H 5 3 ) 2 Zn+2H 2 (12.89 per cent. 

 H 2 0). The loss in weight must therefore be 12.89 per cent. 



Digestion with water containing chloroform is a very convenient 

 method for the preparation of the xanthine bases. Five hundred 

 grams of finely divided meat are placed in a glass-stoppered bottle, or 

 divided between two bottles, with 5 liters of chloroform-water (5 cc. 

 of chloroform to 1 liter; in this case ordinary water may be used), 

 then a few drops more of chloroform are added, and the mixture is well 

 shaken. 



1 The presence of the sulphuric acid may be avoided if phosphoric acid 

 instead of sulphuric acid is used to acidify. 



