1903.] PUBLIC DOCUMENT — No. 33. 155 



fed is only one, and possibly by no means the most impor- 

 tant, of these conditions. It is, however, believed that the 

 question of the proper combination of nutrients has its 

 importance. It is recognized that the problems arising are 

 difficult ; but the investigations will be continued, in the 

 full belief that the results of faithful work will prove of 

 ultimate value. 



