THE DIGESTIVE SECRETIONS 927 



as gastric secretin or gastrin, which is hberated during the process 

 of gastric digestion and serves as a stimulus to the local glands. 

 Secondly, it cannot be doubted that food itself contains certain 

 stimulating substances which upon their absorption exert a definite 

 synthetic or constructive influence upon all cellular processes. These 

 accessory bodies are known as vitamines. Practically nothing is 

 known regarding their chemical nature/ but we divide them as a rule 

 into two groups, viz. : those soluble in fat which are abundant in but- 

 ter, ^ and those soluble in water and alcohol which are present in wheat, 

 maize, cabbage, and in many foods of animal origin. 



It must seem strange that an animal fed upon a mixture of pure proteins, 

 fats, carbohydrates, salts and water, will not thrive, but ceases to develop and pres- 

 ently exhibits a complex of symptoms indicative of malnutrition. But if this 

 artificial diet is augmented by some natural food, such as vegetables or milk, the 

 animal immediately begins to develop normally. Hopkins^ divided a large number 

 of young rats into two groups, one of which received a diet of caseinogen, fats, 

 carbohydrates and salts, and the other the same food plus a small ration of fresh 

 milk. Although the consumption of material was practically the same in both 

 groups of animals, the former soon ceased growing, while the latter developed 

 normally. Even man may suffer from these "deficiency-diseases," chief among 

 which are scurvy, beri-beri, pellagra and rickets. Scurvy, for example, used to be 

 prevalent upon sailing vessels when fresh meat, vegetables and fruits were unob- 

 tainable, and when fish formed the almost constant diet. As a means of preventing 

 this disease, lime or lemon juice was generally given, it being believed that citric 

 acid and traces of malic acid are essential constituents of food. Scurvy may also 

 develop in infants fed exclusively on pasteurized milk. All the alarming symptoms 

 of this disease may be made to disappear in the course of a day or two by the use 

 of fresh milk or by the addition of orange juice and the white of egg to the former. 



Very similar disturbances of nutrition may be incited by the exclusive use 

 of polished rice. Thus, it has been noted in Japan that Kak-Ka (beri-beri) has 

 greatly increased since the primitive mill-stones have been displaced by the 

 modern steel-rollers. In Bengal, on the other hand, where the old methods of 

 milling are still in use, this disease is practically unknown, although rice forms one 

 of the chief foods of this country. A similar disease may be evoked in birds by 

 feeding them only polished rice. This puzzling situation has been cleared up in a 

 large measure by Funk,^ who has extracted from the polishings, i.e., from the 

 outer coats of the rice kernel, a basic principle which he calls vitamine. Further- 

 more, it has been found that if these polishings, or their alcoholic extract, are added 

 to the rice prepared in the modern way, this food does not produce the aforesaid 

 disease. After its development, the latter may be quickly remedied by the in- 

 gestion of unpolished rice or by eating potatoes, fresh vegetables, fruit, milk, meat 

 and eggs. Yeast is said to contain vitamines in considerable amounts and it is 

 assumed that the nutritive value of fermented beverages, such as beer, is in large 

 part due to these bodies. Quite similarly, it is assumed that the value of whole- 

 meal bread does not depend upon its extra amount of protein but probably upon 

 its content in vitamines. 



It must be concluded, therefore, that the different foods taken into 

 the stomach contain certain substances which in themselves cannot 

 be regarded as foods nor as condiments, but which are absolutely 



1 McCoUum, Simmonds and Fitz, Am. Jour, of Physiol., Ixi, 1916, 361. 



2 Osborne and Mendel, Jour, of Biol. Chem., xxiv, 1916, 37. 



3 Jour, of Physiol., xliv, 1912, 425. 



4 Ergebn. der Physiol., 1913, 124. 



