THE SOLUTIOX OF ANALYTICAL PROBLEMS. 251 



Exa»ij)Ie b.^The milk was curdled, and the whey was- 

 analysed. 



Acidity, 

 Total solids, 

 Fat, . 

 Ash, . 

 Solids not fat, 



43-1° 

 6-25 per cent. 

 1-05 „ 



0-4S 

 5-2U 



From the low percentage of solids not fat and ash of the whey, 

 it was concluded that about 15 per cent, of water had been 

 added, and there was some probability that this water con- 

 tained an acid. It may also have been watered milk which has 

 gone sour. 



Exmnyle c. — The milk was curdled and the whey analysed. 



The analytical figures weie : — 



Acidity, . . 35-2' 



Total solids, . . . 7-4() per cent. 



Fat, . . ... 0-88 



Ash, . O-IJO 



Solids not fat, .... 6-58 „ 



It was concluded from the normal percentage of solids not fat 

 and ash of the whey, that nothing had been added and that the 

 milk had become sour by natural causes. 



Exaiii/ple d. — The milk was curdled and the wlicy analysed. 

 It was slightly bitter and gave a pink biuret reaction. 



The analytical figures were : — 



Acidit}', 

 Total solids. 

 Fat, . 

 Ash, . 

 Solids not fat. 



20-8' 



11-13 per cent. 



3-03 



0-09 



8-10 



The alkalinity of the ash to phenolphthalein was equal to 

 0-025 per cent. iSTajCO^. 



It was concluded that the milk had been peptonised, and was 

 insufficiently alkaline. 



Example e. — The milk was curdled and the whey analysed. 



The following were the analytical figures : — 



Acidity, . 26-2' 



Total solids, , . 9-42 per cent. 



Fat, . . 1-27 



Milk-sugar, . . . 5-53 ,, 



Ash, ... . . OGO 



Solids not fat, . 8-15 ,, 



The milk was not bitter, but gave the biuret reaction. 



It was concluded from the low acidity and the high milk- 

 sugar that lactic fermentation was not the cause of curdling ; 

 from the biuret reaction being obtained, it was concluded that 

 an enzyme was the cause. 



