144 



MILK HYGIENE 



the advantage only when it is a question of keeping the 

 milk a long time or transporting it a long distance, and 

 in this case the principle followed is essentially the 



FIG. 11. 



Section, to show construction of apparatus shown in Fig. 10. a, entrance for milk; 0, 

 exit for milk ; c, steam-chamber ; d!,steam-opening ; e, safety-valve. 



same as that followed in the preparation of preserves in 

 hermetically sealed cans. Considerable advance has 

 been made in recent years in regard to the preparation 



