VITAMINES 



243 



the protein-free milk. The animal eventually succumbed to 

 diseased lungs after 587 days of experimental feeding. Provided 

 that a suitable protein, as casein or edestine, is included in the 

 diet, it can be said that rats may be maintained practically 



32c 



300 



260 



260 



240 



2201 



200 



Fig. 14. — The plain line shows weight during feeding with artificial diet, and the crossed 



line the weight after the change to milk diet. 



(From the Journal of Biological Chemistry, vol. xvi. 1913.) 



indefinitely so long as the maintenance vitamine, such as is 

 found in dried protein-free milk, is present. 



But maintenance is one thing and growth is quite another, 

 and Osborne and Mendel have found that, although the addition 

 of protein-free milk to the artificial diet is sufficient to render it 

 capable of maintaining the health of fully grown rats, it is 



