PRESERVATION OF MILK AND ITS TREATMENT 97 



water to cow's milk may be gradually decreased. As the infant 

 begins to secrete larger amounts of diastase, oat gruel or other 

 starchy liquids may be substituted for sugar. Infectious germs 

 are destroyed by boiling the milk in a saucepan or a Soxhlet's 

 apparatus. The albumin, which is none too plentiful to begin 

 with, is thus coagulated, while the casein is altered in such a 

 manner that the milk coagulates more slowly and less completely 

 with rennet. The change does not, as was previously supposed, 

 solely consist in the precipitation of certain calcium salts which 

 are a necessary factor in coagulation when the milk comes into 

 contact with the acid gastric juice the effect will be neutralised 

 but, according to the author's investigations 1 , a real denaturing 

 of the casein takes place, which must mean that it becomes less 

 digestible, for the coagulation of casein by rennet is (see p. 13) 



FIG. 60. Orla-J 'enseri ',<? Household Pasteurising Apparatus. 



only a sign that the first stage in digestion has been completed. 

 The fact that raw cow's milk is coagulated into lumps immediately 

 on entering the stomach is regarded by the author as a practical 

 provision against the passage of large amounts of undigested 

 casein through the stomach. Furthermore, the milk acquires a 

 cooked flavour, and its natural enzymes, bactericidal constituents 

 and antitoxins are destroyed. Even though opinions may be 

 divided regarding the practical bearing of all these changes in 

 connection with infant nutrition, it is certain at least that many 

 children cannot stand boiled milk, for which reason it is advisable 

 to employ low temperature pasteurisation in freeing infants' milk 

 from pathogenic germs. Both in order to be on the safe side as 

 regards tubercle bacteria and to avoid the too rapid separation of 

 cream an undesirable feature in infants' milk the lowest tem- 



1 " Landwirtschaftliches Jahrbuch der Schweiz," 1905, p. 241. 



D.B. 7 



