DETERMINATION OF WATER, ASH, AND FAT. 1395 



The ptomaines thus separated are dissolved in water and detected by 

 precipitation with platinum chlorid, gold chlorid, phospho-molybdic 

 acid, and phospho-tungstic acid. They also yield prussian blue on 

 being treated with potassium ferrocyanid and ferric chlorid. 



DETERMINATION OF WATER. 



About 2 grams of the macerated meat are weighed into a tared flat- 

 bottomed dish and dried to constant weight at the temperature of 

 boiling water. A flat- bottomed aluminum dish answers admirably for 

 this purpose. On account of the oxidation of the fat, meats may be 

 dried with advantage in a current of hydrogen or in vacuo, although 

 satisfactory results are obtained in the open air. The drying usually 

 requires about five hours. 



DETERMINATION OF ASH. 



Dry about 2 grams at the temperature of boiling watei . Thoroughly 

 carbonize, exhaust the charred mass with water, filter and wash with- 

 out transferring more than necessary of the char to the filter. The 

 filter paper and contents are placed in the dish and ignited at bright 

 red heat. The color of the fully ignited ash of meat or meat prepara- 

 tions will, usually, vary from light gra} T to dark gray. The ash of 

 canned meat preparations is often colored by iron from the tin plate. 



The filtrate containing the soluble ash is then returned to the dish, 

 evaporated to dryness after the addition of a few drops of ammonium 

 carbonate solution, heated to very low redness, and weighed. 



Satisfactory results may often be obtained without extracting, by 

 igniting at low redness a very thin layer of the preparation on a 

 porcelain crucible cover. 



DETERMINATION OF FAT. 

 DETERMINATION. 



The residue from the determination of moisture is transferred to 

 the extraction tube as completely as possible, with the assistance of a 

 glass rod. The fat adhering to the dish is washed into the extraction 

 tube by means of ether. The tube is placed over a weighed flask in 

 the apparatus which is to be employed, and the substance extracted 

 with anhydrous alcohol-free ether for at least sixteen hours. In case 

 the meat is not finally divided, the operation may be interrupted with 

 advantage, the meat ground in a mortar with sand, and again trans- 

 ferred to the extraction tube, with the assistance of ether. It has 

 repeatedly been demonstrated that the fat of meat can not be com- 

 pletely extracted by ether without previous digestion with pepsin. 

 At the same time the method here given is satisfactory for compara- 

 tive work on commercial samples. The fat was determined in the 

 meats hereafter described by Mr. W. H. Krug. 



