The Vitamine Manual | Page 8

Protein, 18; starch, 26; protein free milk, 28; lard, 28. In the part of the periods marked butter, 18 per cent of butter was substituted for an equal amount of lard.
II (from _Jour. Biol. Chem._, 1913, xv, 311). Shows recovery on addition of butter fat to a diet containing all the nutrients and artificial protein free milk. These diets contained the following percents: Protein, 18; lactose, 23.8; starch, 26; milk salts, 4.2; total fats, 28.
III (from _Journ. Biol. Chem._, 1915, xx, 379). These show the effect of various sources of vitamine A such as egg fat, butter fat and oleomargarine. The broken line parts show the failure of laboratory prepared lard to better the commercial lard of the basal diet and the crossed lines the immediate effect when a true source of vitamine A was added. Basal diet: Protein, 18, protein free milk, 28; starch, 24-29; lard, 7-28; other fats, 0-18.
IV (from _Journ. Biol. Chem._, 1913-14, xvii, 401). This chart shows the failure of almond oil as a source of vitamine A and the prompt recovery when butter fat or cod-liver oil was used. Basal diet: Edestin, 18; starch, 28; protein free milk, 28; lard, 8; almond oil or butter fat or cod-liver oil, 18.]
With these points cleared up each nutrition investigator returned to an analysis of his food mixtures and proceeded to the location in sources of the various factors. The years 1912-1918 are mainly contributory to further knowledge of the properties of these two vitamines, their reactions, source, behavior, etc. In 1912, however, Holst and Fr?hlich began a study of scurvy that was to culminate later by adding to the list a new member of the family, viz., vitamine "C."
The disease of scurvy and its prevention by use of orange juice potatoes, etc., was a well known phenomenon and to the curative powers of lime juice we owe the name "lime-juicers" as a synonym for the British merchant marine.
Following his discovery of vitamine as the preventative substance to beri- beri, Funk had outlined a theory of "avitaminoses" as the responsible cause of several other types of diseases, including scurvy, rickets, pellagra, and beri-beri. In other words, he suggested that the etiology of these diseases would be found to lie in the lack of the vitamine factors. His views at the time were largely hypothetical since the only one of his avitaminose then demonstrated was beri-beri, but the hypothesis attracted attention and developed a new method of study as it had in matters of normal nutrition.
Between 1907 and 1912 Holst and Fr?hlich had made exhaustive studies of the causes of scurvy and had reached the conclusion that its cause was due to the absence of some factor, admittedly unknown, but as strongly indicated as in the case of beri-beri. Holst pointed out that a guinea pig restricted to a diet of oats became affected with scurvy. McCollum as well as others were attracted to this problem and in 1918 McCollum stated that scurvy was not due to a lack of a dietary factor but to the absorption from the intestine of the poisonous products resulting from abnormal decomposition of the food and especially of protein food. He studied the guinea pig on an oat diet and drew the conclusion that while it does induce scurvy this result is not due to the absence of any specific factor in the oat diet. He showed that while the oat kernel contains all the chemical elements and complexes necessary for the growth and health of an animal these elements are not in suitable proportions. It lacks certain mineral salts and its content of the "A." vitamine is too low to permit oats alone to give satisfactory growth results. Furthermore its proteins are not of as good quality as those of milk, eggs, and meat. By merely supplementing the oat diet with better protein, salts, and a growth promoting fat, he reported that a guinea pig could be developed normally without further addition and that therefore it was impossible to show that any unknown factor was responsible for the scurvy symptoms. McCollum also reported that the guinea pig could develop scurvy even when his diet was supplemented with fresh milk and since milk was a complete food it followed that the cause of the disease must be sought outside of dietary factors.
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