Milk Sugar. 231 



is sufficient. When the curd has formed, which 

 will be as soon as the acid is thoroughly mixed 

 with the milk, the whey is drawn off and the 

 curd washed 'two or three times with warm water. 

 It is then taken out and pressed as dry as possible, 

 after which it is ground rather fine in a peg mill 

 and then dried in an oven till perfectly drj^ The 

 amount usually realized from the skimmed milk in 

 this way is not more than may be realized when 

 it is skilfully fed to animals. 



Milk sugar. — Milk contains between 4 and 5 per 

 cent of milk sugar, and the manufacture of this sugar 

 has come to be an important industry. In the manu- 

 facture, whey is preferably used, or if skimmed milk 

 the casein is first coagulated and removed. The 

 water is then removed by evaporation until the crys- 

 tals of sugar are formed. Various methods are used 

 to rid the sugar of albumin and other materials con- 

 tained in the whey. Formerly this was a somewhat 

 difficult operation, and added considerably to the ex- 

 pense of the manufacture, but recently improvements 

 have been made in this respect, so that the cost of 

 the manufacture of the sugar is much lessened. The 

 growth of the industry has been very rapid, result- 

 ing in a much lower price for the product and a very 

 much increased consumption. Formerly, almost the 

 only use of milk sugar was medicinal. Now, be- 

 cause of its digestibility, it forms an important in- 

 gredient of many of the so-called infants' and inva- 

 lids' foods. It is usually prepared in the form of a 

 white crystalline powder, only mildly sweet to the 

 taste. 



