Since it has been found possible to obtain potent concentrated extracts of the A vitamin from the grasses, there seems no reason why it should not be possible to enrich a vitamin-poor fat with such extracts and thus remedy the only nutritional defect of the butter substitute. Meantime it is not necessary to avoid the use of the margarines on this ground, provided a sufficient amount of A is supplied from other sources. The enemies of oleomargarine have been criticised for making a seemingly unwarranted trade use of data on the very limited content of A in margarines. It is neither reasonable nor fair to the very important and essential vegetable or nut-butter industry to condemn these products on the ground that vitamins are not present. The amount of animal fats produced is hopelessly inadequate to supply the world's requirements. Vegetable fats necessarily must form a part of the diet of mankind. We deplore the attempts to play upon the defect for trade purposes. Instead, endeavors should be put forth to improve the body-building values of vegetable fats by the addition of vitamin concentrates to these fats.

Whole milk cheese is fairly rich in A and may contain a small amount of B as well although it cannot be regarded as a satisfactory source of this vitamin. Skim-milk cheese is practically vitamin-free.

Eggs are rich sources of A and B. The fat of egg-yolk is as efficient as butter-fat in growth-promoting power. Twenty grams of dried whole egg (about half an egg) was sufficient to cure a polyneuritic pigeon. There is no evidence, however, that they possess any antiscorbutic power. A diet of milk and eggs, whether raw or cooked, would therefore supply an abundance of the A and B vitamin but can with advantage be supplemented with respect to C.1

Cooked meats add little to the vitamin content of the diet. Some A may be present in the fats, and small quantities of B and C may be obtained from the lean muscle tissue, but in general meat and fish may be disregarded as a source of vitamins unless used more extensively than would be advantageous for the average individual in civilised life. The glandular organs are exceptions to this, however, the liver and kidney being rich both in A and B. The pancreas (sweetbreads) and brain also contain considerable amounts of B. McCollum1a states that it is possible to select foods so as to secure a fairly satisfactory diet entirely derived from animal tissues, provided the ration is not limited to muscle tissue. When blood, liver, kidney, and other glandular tissues are selected, together with a certain amount of bone substance, the food supply is sufficiently good to provide for normal development. Young animals cannot grow or remain long in health, however, when restricted to muscle tissue as the sole food. With reference to this it is pointed out in an editorial in the American Medical Journal 2 that the avoidance of glandular organs on account of their high purin content is probably unnecessary.

Over-eating of glandular tissue is likely to be unwholesome. " But assuming moderation of diet on the part of a healthy man in a regimen in which liver and its analogues are consumed as adjuvants rather than fundamentals in the ration, it is likely that they may often exercise a wholesome and even corrective influence in supplying food factors which the cereals, roots, tubers, and even muscle tissue lack".

1 The value of vitamins contained in ice cream is discussed by Jaffa. (Chem. Abe. 1021, 2510).

Concerning Farmers' Bulletin 1207 issued by the States Relation Service, Department of Agriculture, the American Food Journal (November, 1921, 24) notes that the discussion of vitamins in this bulletin marks the complete acceptance of these discoveries by the States Relations Service. Referring to the vitamin A, found especially in milk fat, the bulletin says: "Vitamin A is of special importance for two reasons: one is that without it children cannot grow and develop normally, even though their food is otherwise sufficient for their needs; the second is that vitamin A is found in such foods as milk, egg yolk, green leaf vegetables, fats surrounding the vital organs, organs of animals, to a less extent in meat, and perhaps in certain fruits and in few so abundant as in milk. It appears to go with the milk fat and so is found in whole milk, cream and butter".

1a McCollum, Proc. Inst. Med. Chic. 3, 13, 1920.

2 Am. Med. J. 75,1206,1020.

Since milk and eggs are used on the whole rather sparingly in the diet of the average adult and meat is not a very abundant source of vitamins, the vegetable foods must form the main source of supply of these factors. It is unfortunate that flour, which makes up so large a proportion of the daily ration, should have been robbed of its vitamin content in the milling process, but the refined product of the modern mills is useless as a source of vitamins. Whole wheat bread furnishes both A and B, and the combination of whole wheat bread and butter, milk, and fruit is an admirable one as regards vitamins.

Apart from the cereal grains the seeds commonly used as foods contain no quantity of A. Peas and beans, fresh or dried, furnish a fair amount of B. C appears to be lacking, except on germination.

Tubers and roots differ surprisingly in their content of vitamins, so much so that no generalization can be made. The white potato, the most extensively used root vegetable, is relatively poor in both A and B, but may serve as an effective antiscorbutic if supplied liberally. Sweet potatoes have a higher concentration of A than white potatoes. The common yellow turnip (swede or rutabaga) is a good source of all three vitamins, although the antiscorbutic is somewhat decreased by the necessary cooking. Carrots contain about equal amounts of A and B, but are much poorer in antiscorbutic than the rutabaga. Beet-root is comparatively poor in all three vitamins.

The leafy vegetables, spinach, cabbage, and lettuce, are exceptionally rich in A, spinach being the richest and lettuce the poorest of the three, and are also excellent sources of B and C. The same statement may be made of the tomato. These four vegetables are commonly regarded as luxuries rather than necessities, and are generally used chiefly to give variety to the menu. Our recently acquired knowledge of the vitamins indicates, however, that they should play a much more prominent part in our diets. McCollum has placed a great deal of emphasis on the value of the leafy vegetables which he classes along with milk as protective foods. He points out that while these vegetables might at first sight appear to be uneconomical foods, owing to their low content of carbohydrate, fat, and protein and high content of water, they have nevertheless a peculiar value owing to their high vitamin and mineral content and should be used as liberally as possible.