How Vitamins Were Discovered : Part 5

The Vitamine Manual
by Walter H. Eddy

(Page 5 of 11)

Examination of guinea pigs that died of scurvy showed that the cecum was always full of putrefying feces. This observation suggested that the mechanical difficulty these animals have in removing feces from this part of the digestive tract might have something to do with the disease. McCollum and his workers were confirmed in their views by the excellent results that followed the use of a mineral oil as a laxative. Another piece of evidence they gave for their views was that when animals were fed on oats and milk the onset of the scurvy could be delayed by merely adding the cathartic, phenolphthalein, to the mixture. They met the argument of the curative power of orange juice by preparing an artificial juice of citric acid, inorganic salts and cane sugar and showing that this synthetic mixture which held only known substances was capable of protecting animals from scurvy over a long period of time.

Without going further into the evidence presented by these workers McCollum was sufficiently convinced of the correctness of his own views to not only state them in his researches but to set them forth at length for public information in his book entitled The Newer Knowledge of Nutrition. In spite of all this evidence his views failed to convince the holders of the vitamin hypothesis. Harden and Zilva and Chick and Hume in England freely criticised his conclusions because whole milk was used in his experiments and no attention paid to the amounts eaten. It was then well known that if enough whole milk is eaten scurvy will not develop. Cohen and Mendel autopsied normal guinea pigs and found that the cecum was nearly always full of feces. On the other hand in autopsies of many pigs dead from scurvy only one-fourth were found to show the impaction of feces claimed by McCollum as cause of the disease. Milk is constipating to guinea pigs. Large amounts of milk should therefore have increased scurvy if the cause stated by McCollum was the real one. On the contrary large amounts of milk prevented scurvy and small doses permitted it to develop. The use of coarse materials as a preventative of constipation failed to prevent scurvy onset. Hess and Unger found that cod-liver oil and liquid petrolatum prevented constipation but failed to prevent scurvy.

The attack on the McCollum view continued from various quarters. Chick and Hume in England examined his grain and milk fed series and showed that those receiving much milk and little grain recovered while those on the reverse diet died. They held that all guinea pigs with scurvy become constipated regardless of the diet. They gave large quantities of dried vegetables well cooked in water, in order to provide bulk, but this did not prevent scurvy and neither did the use of mineral oil. Hess found that in infants with scurvy there is a history of constipation but that while potatoes which are not laxative cure scurvy, malt soups which are laxative permit its development. He found that scurvy in infants is relieved by amounts of orange juice entirely too small to have a marked laxative action and was unable to secure cures with McCollum's artificial orange juice. The most convincing argument was the discovery that orange juice administered intravenously still exerted a curative action which could not in any way be laid to its effect on constipation.

To these attacks McCollum's co-worker, Pitz, suggested a new hypothesis. It was well known that in rats and man the intestinal flora can be changed from a putrefactive form to a non-putrefactive type by feeding milk sugar or lactose. If this were true, as was admitted by all, and the scurvy due to the absorption of putrefactive products, this absorption might still be the causal factor whether constipation was present or absent. To determine this point he fed his guinea pigs on oatmeal to which he added a carbohydrate diet. When the carbohydrate was lactose he was able to cure and prevent scurvy. This evidence was not considered convincing, however, since in his experiments milk was given freely. Furthermore, Cohen and Mendel demonstrated that in their experiments pure lactose neither prevented nor cured scurvy while Harden and Zilva could find no antiscorbutic value in either cane sugar, fructose, or sirup. These authors believed and stated that Pitz's results were entirely attributable to the free use of raw milk.

As this milk factor came increasingly to the attention in the controversy it was natural that students began to reëxamine this product more carefully. The vitamin advocates at first believed that its potency as an antiscorbutic was of course due to the vitamins already found present therein, viz., the "A" or the "B." But there began to be difficulties with this view. Hess found that eggs and cod-liver oil, both rich in "A" were of no value as scurvy cures. These experiments eliminated the "A" as the curative factor. Cohen and Mendel used a mixture of yeast and butter in their experiments without success. These experiments threw doubt on the "B" as a curative factor. Studies in heated milk had also shown that the scurvy curing power was destroyed by such procedures as heating and that pasteurized milk was not as good as raw milk. This heating on the other hand did not destroy the antineuritic power of the milk nor its growth- stimulating properties. The combined result of all these studies was to eliminate both the "A" and the "B" as the vitamins with antiscorbutic power without suggesting a better hypothesis than McCollum's.

Gradually, however, it became evident that while scurvy is not prevented by either of these vitamins Funk's hypothesis and Holst and Fröhlich's experimental evidence was correct and McCollum's view wrong. The answer lay in the discovery of a third vitamin, water-soluble like "B" but otherwise of entirely different behavior and properties. J. C. Drummond of England finally suggested its inclusion in the family and the name water- soluble "C." As soon as its presence was admitted and its properties roughly determined the way was opened to development of the antiscorbutic vitamin hypothesis and that has now proceeded as rapidly as in the other fields. During the past year many contributions have been made in this field. Sherman, La Mer, and Campbell have recently published results that have taught us much about the measurement of this new member and its manipulation in experimental study of scurvy.

The year 1920, then, has brought us to a recognition of at least three members of the family. Still more recently another deficiency disease has been under investigation and Hess has found in cod-liver oil a remedy for rickets that he cannot believe owes its efficiency to the "A" type. Mellanby of England believes the "A" vitamin is the preventive factor in this disease but Hess's results at least suggest the possibility that the antirachitic vitamin may be separate and distinct from any of those yet named, possibly vitamin "D?" Others are beginning to doubt the identity of the rat growth promoter and the beri-beri curing complexes and feel that the "B" itself may be the name of a group instead of a single entity. All of these features make one feel uncertain to say the least, as to the limits of this vitamin family or of the future possibilities but enough has been given to indicate the historical development to date and we can now turn to more special features of the subject and their bearing on every day affairs.