With this understanding of the experience and views of the various investigators of the subject of nutrition, it is of interest to look back from our present position and point out the problems waiting to be solved.

There had been in the literature of pathology for many years abundant evidences from human experience that a diet may have an appropriate chemical composition and yet be unsatisfactory for the nutrition of man. These observations did not secure from students of nutrition the attention they merited. It had been known for centuries that certain diets of stale foods produced outbreaks of scurvy among sailors, soldiers, prisoners and others, and that fresh vegetables and fruits would promptly relieve the trouble if they were taken in the early stages of the disease. Nobody had, however, even in the first decade of the twentieth century, made an effort on a comprehensive plan to discover what it was in certain foods which caused them to be incomplete and to induce disease, and what it was in certain other foods which made them of specific therapeutic value.

Beri-beri, a peripheral neuritis resulting in paralysis, had been known from remote times. In 1884 it was demonstrated beyond doubt by the Japanese Navy that it was due to faulty diet. Under the direction of Admiral Takaki a ship made a cruise of eight months, during which time the incidence of beri-beri among the sailors was carefully noted. Another ship was then manned and sent on a second cruise over the same course, but with an improved dietary furnished the men. The effects were so striking that the diet of the army and navy was remodelled and improved, with the result that thereafter the disease practically disappeared. In 1897 Eijkman, a Dutch physician, sought to test the question whether there was any relation between the consumption of polished rice and the incidence of beri-beri. He found that pigeons or chickens that were restricted to a diet of milled rice developed in two to four weeks a condition of paralysis strikingly suggestive of beri-beri in man. He established the relation between milled rice and the disease, and showed that there was something in the bran layer which protected against it. Although several pathologists had repeated and confirmed this observation, it did not influence students of nutrition until after Funk, a Polish chemist, called attention to this work in 1910, when he designated the term "vitamine" to indicate a group of indispensable nutritive complexes (4).