576 voegtlin: role of vitamines in nutrition 



tance of the presence in the diet of man of small quantities of 

 substances essential for the maintenance of health. Until very 

 recently physiology taught that the human diet should meet the 

 following requirements: (1) It should contain an adequate amount 

 of protein, fat, carbohydrate, and inorganic salts; and (2) the 

 daily ration should conform to certain definite requirements in 

 regard to its caloric or fuel value. . Once these requirements were 

 met the diet was considered as being physiologically satisfactory. 

 However, a number of unexplained facts did speak in favor 

 of the assumption that the human diet should also contain some 

 other substances, so-called accessory dietary constituents. For 

 instance, it has been known for some time that scurvy is a disease 

 which occurs in man and certain higher animals when the diet 

 does not contain fresh vegetables or animal foods. Epidemics 

 of scurvy broke out on sailing vessels when the crew was forced 

 to live for several months on such food as canned beef and dried 

 cereals to the complete exclusion of food in the fresh state. 

 During the siege of Paris in the year 1871 part of the population 

 was also deprived of fresh food and an epidemic of scurvy 

 appeared. Scurvy was apparently due to the lack of fresh food 

 in the diet. This conception of the cause of scurvy is supported 

 by the fact that a corresponding change of diet and especially 

 the administration of fresh milk or lemon juice leads to a rapid 

 recovery of most cases affected by this disease. Hence, we might 

 conclude that there exist in fresh food some substances which 

 are essential for the prevention of scurvy. These substances 

 may be designated as antiscorbutic substances. As stated pre- 

 viously, they have no direct relation to the other known dietary 

 constituents such as the proteins, carbohydrates, fats, and salts. 

 The chemical composition of the antiscorbutic substance is still 

 unknown, although numerous fruitless attempts aiming at its 

 isolation have been made. All we know about this substance is 

 that it is fairly stable in acid media. This is probably the reason 

 why lemon juice with its high acidity is the classical preparation 

 used in the prevention and treatment of scurvy. For the same 

 reason fresh milk, having a neutral reaction, on being exposed 



