MEAT AND MEAT PRODUCTS. 



Ill 



often found that the proteids are so completely removed that no precipitate is 

 formed with the double iodid. and nitration is not necessary. 



Add about 2 mg of sodium chlorid per 100 cc of water, precipitate the glycogen 

 again by menus of two volumes of 9G per cent alcohol, filter, wash with 9G per 

 cent alcohol, containing about 7 mg of sodium chlorid per liter, then with 

 absolute alcohol, finally with ether, dry to constant weight, and weigh. 



As a control, invert the precipitated glycogeu by boiling for three hours with 

 hydrochloric acid, diluted with 10 parts of water, and determine the reducing 

 sugar by Allihn's method, multiplying the result by 0.9 to obtain the percentage 

 of glycogen. 



10. Reducing Sugar. Provisional. 



Boil 100 grams of the finely divided meat for fifteen or twenty minutes in a 

 500 cc graduated flask, with a convenient volume of water. Add a few cubic 

 centimeters of normal lead acetate, cool to room temperature, make up to the 

 mark with water, and filter through a folded filter. Remove the lead and 

 determine reducing sugar as dextrose, as described under " VI. General 

 Methods," page 49. 



11. Potassium Nitrate, 

 (a) SCHLOSING-WAGNER METHOD.** PROVISIONAL. 



Use a flask of about 250 cc capacity with a rubber stopper having two holes. 

 Through one of them pass the stem of a funnel carrying a glass stopcock ; the 

 other carries a delivery tube leading to the receiving vessel. Bend the end of 

 the delivery tube so that it will pass easily under the mouth of the measuring 

 burette and cover with a piece of rubber tubing. 



Place 50 cc of saturated ferrous chlorid solution and the same quantity of 10 

 per cent hydrochloric acid in a flask. Prepare the ferrous chlorid solution by 

 dissolving nails or other small pieces of iron in hot hydrochloric acid and keep 

 in glass-stoppered flasks of about 50 cc capacity, entirely filled. The contents 

 of one flask is enough for about twelve determinations, and by using the entire 

 contents of a flask as soon as possible after opening all danger of oxidation is 

 avoided. 



Boil the contents of the flask until the air is driven off; then place the 

 delivery tube under the measuring tube, which is filled with 40 per cent potas- 

 sium hydroxid, add a few drops of water, and cover the tube with pieces of 

 filter paper. By a careful and quick inversion the measuring tube can be 

 brought into the vessel receiving it without any danger of air entering. 



Extract 100 grams of finely macerated meat by boiling repeatedly with suc- 

 cessive small portions of water, concentrate the aqueous solution to a small 

 volume, transfer to the funnel, and, with continued boiling, allow it to pass 

 drop by drop into the flask. When the solution has almost all run out, wash 

 the funnel with three 10 cc portions of 10 per cent hydrochloric acid and allow 

 these portions to pass drop by drop into the flask. The temperature of the sur- 

 rounding water will soon be imparted to the contents of the tube, and the 

 volume of nitric oxid is read with the tube in such a position that the level of 

 the water within and without the tube coincides. 



The amount of nitric oxid present and the corresponding percentage of nitrate 

 may be calculated in the usual way for the given temperature and barometric 

 pressure, or, to avoid computation, the amount of nitrate may be determined 



" Cie'.er and Schneidewind, Die agrikultur-chemiscbe Versuchsstatlon Halle a/S, 1892, 

 |>. 50; Wiley, Principles and Practice of Agricultural Analysis, 1897, 2: 228. 



