260 § 133. FODDER AND FOOD. 



to boiling, add a few drops of milk of lime, whereby a 

 heavy precipitate is usually produced ; then filter the 

 liquid through granular animal charcoal, free from dust, 

 and repeat this filtration until the solution is sufiiciently 

 decolorized. If any evaporation of the water is avoided 

 in the course of this operation, the sugar can be deter- 

 mined at once in a measured portion of the filtrate ; other- 

 wise, the coal must be well washed, the filtrate and wash- 

 ings perfectly mixed, and the estimation of the sugar, for 

 the whole amount of solution taken originally, based upon 

 the ratio between the volume of this solution and that in 

 an aliquot part of which the sugar is determined with the 

 cupric solution. 



e. Ammonia* — Treat 30 c.c. of the sap with enough 

 plumbic acetate to efiect complete precipitation, filter the 

 liquid, and use 20 c.c. of the filtrate for the determination 

 by Schlossing's process (§ 47, h), 



f. Nitric acid. — Determine this according to Schloss- 

 ing's process (§ 62, a), in 10-20 c.c. of the concentrated 

 sap, containing not more than 2-2.5 grms. of organic mat- 

 ter ; an amount of ferrous chloride, containing 6-7 grms. 

 of metallic iron, should be used for 1 grm. of dry sub- 

 stance in the quantity of sap taken. 



Hugo and Ernst Schulze found it best to make an alco- 

 holic extract of from 4-10 grms. of the dried and powder- 

 ed root, according to its richness in nitric acid, with 90° |„ 

 alcohol, with the aid of heat ; the extract was evaporated 

 to dryness, the residue dissolved in water, and the solu- 

 tion filtered, if necessary ; nitric acid was determined in 

 this filtrate. {Landwirthsch. Versuchs-zStatlonen, 9, 447.) 



ff. Starcll. — Some roots, and particularly carrots, con- 

 tain a notable quantity of starch. To estimate it, mash 

 an amount of the root containing 3-4 grms. of dry sub- 

 stance with cold water, rinse the mixture into a beaker, 

 add more water, stir the whole, and let it stand half an 



