1404 



FOODS AND FOOD ADULTERANTS. 



bent so as to pass easily under the mouth of the measuring burette, 

 and is covered with a piece of rubber tubing. 



Fifty cubic centimeters of saturated ferrous chlorid solution and the 

 same quantity of 10 per cent hydrochloric acid are placed in the flask. 

 The ferrous chlorid solution is obtained by dissolving nails or other 

 small pieces of iron in hot hydrochloric acid, and is kept in glass- 

 stoppered flasks of about 50 cc capacity, entirely filled. The con- 

 tent of one flask is enough for about twelve determinations, and -by 

 using the whole content of a flask as soon as possible after opening 

 all danger of oxidation which would take place in a large flask fre- 

 quently opened is avoided. 



The contents of the flask are boiled until all the air is expelled. 

 The boiling is continued for some time, and when no more air escapes 

 the end of the delivery tube is brought into a measuring tube which 



FIG. 1. Schlosing- Wagner Apparatus. 



is filled with 40 per cent potassium hydroxid and the estimation is 

 commenced. 



One hundred grams of the finely macerated meat are extracted by 

 boiling repeatedly with successive small volumes of water, and the 

 aqueous extract concentrated to a small volume transferred to the fun- 

 nel, and with continued boiling allowed to pass drop by drop into the 

 flask. When almost all has run out the funnel is washed with three 

 10 cc portions of 10 per cent hydrochloric acid, and these portions are 

 allowed to pass drop by drop into the flask. The temperature of 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 position that 

 the level of the water within and without the tube coincide. 



The amount of nitric oxid present and the corresponding percentage 

 of nitrate may be calculated in the usual way for the given tempera- 



