PART V. 



THE USE OF MILK FOR INFANTS 



The advantages of milk as a general food for man 

 are so well known that no further discussion is neces- 

 sary ; but the special use of milk for infants, as a sub- 

 stitute for mother's milk, offers certain points of inter- 

 est which merit further consideration. It is logical first 

 to review the behavior of milk and the changes that 

 occur in it during digestion. 



Under the influence of the gastric juice, the proteids 

 undergo a process of splitting up in the stomach. The 

 albumin and globulin are first changed into syn- 

 tonin and then separated into albumoses and, probably, 

 peptone. Casein behaves somewhat differently. It is 

 transformed by the hydrochloric acid of the gastric juice 

 into an acid calcium salt and then, under the influence of 

 rennin, it undergoes a change, during which whey albu- 

 min is formed, into calcic paracasein, which separates as 

 a curd. The calcic paracasein is then split by pepsin into 

 albumin and paranuclein (pseudoneuclein) which is pre- 

 cipitated but which is afterwards dissolved by the pro- 

 longed action of the gastric juice, being broken up into 

 an albumin-like material and phosphoric acid. The albu- 

 mins that are formed by splitting of the casein are later 

 changed into albumoses (caseoses) and peptone. Ac- 

 cording to recent investigations it appears that these 

 substances may undergo still other changes before they 

 are absorbed. Through the action of rennin, an albu- 

 min-like substance (plastein) is formed and through the 



147 



