To Funk is due the credit of bringing to the attention of all the view that there are certain diseases which result from faulty diet, the fault consisting in a lack, relative or absolute, of one or another of several substances, each of which when present in the diet protects against a specific type of breakdown of the tissues. Beriberi, scurvy, pellagra and rickets were all attributed by him to lack of "vitamines" in the diet. Actually he had experimental evidence of the existence of only one of these specific "deficiency" diseases, beri-beri or polyneuritis, as it is called when produced experimentally in animals. This was the only one of the syndromes enumerated which had been studied experimentally in a manner that could be regarded as affording a basis for judgment as to their etiology.

Human experience had, however, been practically as definite as animal experimentation in demonstrating that scurvy could be cured with certain fresh foods, but not by the same foods in a stale condition. As will be pointed out later, however, there was much difference of opinion as to the cause of scurvy. The vitamins made a great impression on the public mind and justly so. There is nothing more spectacular than the restoration of a pigeon which has been brought to a condition of helplessness by a diet of polished rice. Within a few hours of death it can be brought back to an apparently normal condition by the administration of but an insignificant amount of properly prepared substance.

Funk had no clear conception of the importance of the several factors which go to make up an adequate diet, for in 1910 he knew how to produce but one deficiency disease, polyneuritis or beri-beri. This was effected in the same manner that Eijk-man had done it in 1897, by restricting animals to polished rice as their sole food supply. These observations in pathology failed at that time to impress the students of normal nutrition. Rice is now known to be faulty with respect to four dietary factors for the rat, and with respect to five factors for man.