Further experiments were then conducted to find whether this unidentified substance which was being added accidently as an impurity in the milk sugar was the same as the substance with which Funk and others were dealing in their studies of beri-beri. It was found that pigeons which had developed beri-beri as the result of being fed exclusively upon polished rice could be temporarily "cured" with any preparation which would, when added to a diet of purified food-stuffs containing a growth-promoting fat, cause animals to grow. See chart 3.

Following the method of Funk and Suzuki, McCollum and Davis in 1914 employed alcoholic extracts of various natural foods, adding the alcohol-soluble matter to the standard mixture of purified protein (casein), starch (dextrinized), salts and butter fat, and soon became convinced that the substance which relieves polyneuritis in pigeons was always present in the preparations which rendered the diet of purified food-stuffs capable of promoting growth. An alcoholic extract of ether extracted wheat germ was finally adopted as a source of this dietary factor in later investigations. Funk and his co-workers had previously shown that the curative substance is present in many natural foods (19). Repeated experiments by McCollum and Davis showed that the inclusion of the alcoholic extract of wheat germ or of other food was not sufficient to induce growth unless the butter fat or other similar fat was likewise added to the purified food mixture. Both the growth-promoting fat and the trace of unidentified substance in the alcoholic extract of wheat germ are necessary for the promotion of growth or the preservation of health (22).

Chart 3. - The four groups of curves illustrate the nature of the deficiencies of the polished rice kernel as a food for the rat. Lot 317 could not grow on rice, a complete salt mixture and butter fat because the anti-neuritic substance water-soluble B was absent. Improvement in the protein by the addition of casein did not enable the animals to grow except to a very slight extent. Unpolished rice contains the germ which is rich in water-soluble B, so the addition of the same supplements as in Lot 317 served to complete it and make a diet on which growth was rapid. Lot 401 differed essentially from 324 in that it contained the alcoholic extract of wheat embryo or germ. This supplied water-soluble B, and therefore enabled the animals to grow, since all other deficiencies of polished rice were made good by the addition of a protein (casein), a complete mineral salt mixture and butter fat which contained fat-soluble A.

37. Funk And Macallum Report That Butter Fat Contained No Vitamine

Funk and Macallum found butter fat ineffective for the cure of polyneuritis in pigeons, and accordingly considered it free from "vitamine." They fed young rats a diet of purified food-stuffs supplemented with a liberal amount of butter fat, and found that the animals did not grow. Although this was the result of the lack of the anti-neuritic substance, they were not at that time clear as to the several factors which are necessary in the diet and interpreted their data as evidence that butter fat possessed no growth-promoting properties (23).