GROWTH AND NUTRITION 



85 



Figure 53. A typical case of avian polyneu- 

 ritis, due to a lack of vitamin B. 



polishing process, by which 

 the germ and outer covering 

 of the grain were removed, 

 was largely responsible for 

 the disease. Evidently the 

 rice polishings contain some- 

 thing that is essential for nor- 

 mal nutrition, and this sub- 

 stance is absent from the por- 

 tion we know as polished 

 rice. 



Many ambitious efforts were made to isolate the active mate- 

 rial from rice polishings, but though complete success has not 

 been attained as yet, the results have been at least stimulating. 

 We will not attempt any adequate description of these efforts, 

 but mention the fact that, in 191 1, Funk 22 obtained a few crys- 

 tals of what he believed was the active curative agent, in the 



pure state. He stated that 4 mgm., roughly of an ounce, 



were sufficient to cure a pigeon. It would seem now, however, 

 that these crystals were not the pure curative agent, but that 

 they carried the active agent as an impurity. Funk believed this 

 substance, from a chemical standpoint, is an amine, and that it 

 is of vital necessity. He called it, therefore, "vitamine," and the 

 name has persisted, though we have no evidence that any of the 

 unidentified factors are really amines. 



Probably the next effort of this nature we should mention 

 was that of Osborne and Mendel. 23 They used protein of a high 

 degree of purity, and in addition starch, lard, salts, and sugar. 

 It should be pointed out that their earlier efforts were unsuc- 

 cessful, but they evidently believed the failures were due to 

 some maladjustment of the salts. Accordingly they removed as 

 completely as possible the proteins from skimmed milk, and so 

 obtained, as they believed, essentially a mixture of milk sugar 

 and milk salts. This mixture, "protein-free milk," was dried 



