From what has been said we may now formulate our revised conception of an adequate diet. "The diet must contain, in addition to the long recognized dietary factors - viz.: protein, a source of energy in the form of proteins, carbohydrates and fats; a suitable supply of certain inorganic salts * - two as yet unidentified substances. One of these is associated with certain fats (hence fat-soluble A), and is especially abundant in butter fat, egg yolk fats and the fats of the glandular organs such as the liver and the kidney, but is not found in any fats or oils of vegetable origin. The second substance or group of substances of chemically unidentified nature, is never associated with either fats or oils of animal or vegetable origin. It is widely distributed in natural foods, and can be isolated in a concentrated, but not in a pure form, from natural foodstuffs by extraction of the latter with either water (hence water-soluble B) or alcohol. This water or alcoholic extract always contains the substance which cures polyneurites [polyneurites in birds is comparable to beriberi in man. See the next chapter]. (McCollum.)

Objections to the Use of the Word "Vitamine." In the early part of this chapter we stated that objections were not wanting to the name vitamine.

*So as to satisfy the curiosity of some of my readers, I shall give the composition of a salt mixture that has proved to be extremely successful. I may add that much labor has been expended in the search for suitable salt mixtures. The composition is as follows (the numbers refer to grams): calcium carbonate 134.8; magnesium carbonate 24.2; sodium carbonate 34.2; potassium iodide 0.020; potassium carbonate 141.3; phosphoric acid 103.2; hydrochloric acid 53.4; manganese sulphate 0.079; sulphuric acid 9.2; citric acid 111.1; ferric citrate 6.34; sodium fluoride 0.248; potassium aluminum sulphate 0.0245.

Funk, who coined the word, did so to show its relation to a group of substances known to the chemist as amines; for at one time Funk's experiments led him to believe that these substances are of an amine nature. But never having isolated them, we have really no way of telling. That has led Professor Hopkins in England to suggest the term accessory substance. But Professor McCol-lum's nomenclature, fat-soluble A and water-soluble B, is usually preferred in scientific circles, because, without specifying the nature of the substance, they tell us that there are at least two such substances, and they also tell us something about their solubilities.

But really Hopkins and McCollum's objections are not very impressive. We still speak of organic chemistry, though we really mean the chemistry of the carbon compounds. The word organic came to be used at a time when compounds belonging to this branch of the science were supposed to have something vital in them. But when Wohler disproved this theory chemists still clung to the name. The name had become established in the literature; and so long as we remember to attach no particular significance to the word itself but only to what it represents, we may with much convenience cling to the word organic. And so we do.

Funk coined the word vitamine before McCollum had shown that there were at least two such substances; and the world of science began to use the word accordingly. Why not allow the word vitamine to stand for a group of substances of which fat-soluble A and water-soluble B are examples? We need no more think of vitamine as amine than we need think of organic chemistry as the chemistry of compounds contained in, or produced by, organs. But apart from all this, the word has already crept into the scientific literature. Even the public press is using it. The layman may be tempted to talk vitamines, but he will turn his back scornfully on fat-soluble A and water-soluble B, and perhaps, later on, on something C and another D and so on. We need do nothing further to discourage our lay public in their quest for scientific knowledge.