III. INDUSTRIAL PREPARATION 



211 



addition of concentrated fatty emulsions or propylene glycol solutions of 

 vitamin D2 or D3. Milk can also be fortified by irradiating the cow or feed- 



FiG. ] \. Iii;i(li:it iii^ unit for milk and other aqueous fluids. From the regulating 

 chamber at the left, the milk enters the annular top trough, flows over the weir, 

 and cascades down the wall of the tank to the bottom trough. Carbon arc lamp and 

 fume exit shown swung out of position. Forced air for ventilation enters at bottom. 

 (Courtesy of National Carbon Co.) 



ing the cow irradiated yeast. The vitamin D in irradiated milk, or milk from 

 irradiated cows, presumably is vitamin D3; in milk from cows fed irradiated 

 yeast it is vitamin D2. 



