§ 136. MILK. 263 



to take out the gluten, and again with water ; then pierce 

 the filter with the glass rod, wash its contents into a flask, 

 tear the filter into shreds, and boil it by itself with water 

 CQntaining 4 or 5 drops of 20" \^ sulphuric acid, and finally 

 add it to the contents of the flask ; the total amount of 

 solution thus obtained should not be over 100 c.c. ; pro- 

 ceed as usual with the conversion of the starch into glu- 

 cose (§ 79). 



In most seeds there is but little gnm or sugar ; one can 

 therefore proceed at once to treat the seeds with alcohol 

 acidified with sulphuric acid, as above, remove the alcohol 

 by heat, and convert the starch into glucose. 



MILK. 



136, a. Water. — Boil 50 grms. of the milk with 8 

 grms. of powdered crystalline gypsum, or with 30-40 

 grms. of baric sulphate (§ 90, A), and after the coagula- 

 tion has taken place, evaporate the mixture to dryness on 

 the water-bath, with constant stirring towards the end of 

 the operation, and dry the residue at 100° as long as it 

 loses weight. 



Or, the desiccation may be completed on hot sand in 

 rarefied air (§ 90, </). 



b. Total non-YOlatile matter.— Evaporate 30 grms. of 

 the milk to dryness, with the addition of' a little acetic 

 acid, and incinerate the residue in the muffle at the lowest 

 possible temj^erature. 



c. Protein compounds. — These may be estimated by 

 the remainder left after subtracting the sugar, butter, and 

 ash, from the total dry substance ; this residue consists 

 mostly of casein. Or, nitrogen may be estimated in the 

 usual manner (§ 85) in the residue left on evaporating 6-7 

 grms. of the milk to dryness with powdered gypsum or 

 baric sulphate, as above. 



Albumen is contained in milk in but small proportion ; 



