voegtlin: role of vitamines in nutrition 581 



any chemical relation to the natural vitamine or not, the work 

 just referred to is certainly exceedingly interesting. 



CHEMICAL PROPERTIES OF VITAMINES 



At present relatively little is known regarding the chemical 

 and physiological properties of vitamines. Some facts, how- 

 ever, have been established. The antineuritic vitamine, for 

 instance, is present in the natural foods, largely in a combined 

 form which is soluble in 90 per cent alcohol, or water. This 

 mother substance can be split into the physiologically Tiighly 

 active substance by acid hydrolysis or autolysis by means of 

 enzymes. Very little is known as to the chemical nature of the 

 mother substance of this beri-beri vitamine. The observations 

 that foods rich in lipoids are also rich in vitamines and the solu- 

 bility of the mother substance in alcohol might lead to the belief 

 that vitamines enter into the molecule of certain lipoids, an 

 assumption which recent experiments by Sullivan and myself 

 have made highly improbable. The antineuritic substance is 

 probably not in combination with carbohydrates, as the starchy 

 part of cereals seems to be extremely poor in this substance. 

 The probability that certain parts of the protein molecule (nucleic 

 acid) may hold in combination the active substance is still open 

 for consideration. 



A fact of fundamental importance is that vitamines are fairly 

 susceptible to temperatures above 100°C. A large number of obser- 

 vations made on man and experimental animals show that the 

 prolonged heating of most of the natural foods to a temperature 

 of 120° for one to three hours will destroy most of the physio- 

 logical activity of the vitamines originally present in these foods. 

 Beef which is sub nutted to such treatment is found to lend to 

 symptoms of scurvy in man, if forming the exclusive diet to- 

 gether with other food deficient in vitamines. 



The vitamines which prevent scurvy and beri-beri seem to be 

 fairly resistant to strong acids. As a matter of fact certain acids 

 seem to prevent the deterioration of vitamines. On the other 

 hand, strong alkalies under certain conditions seem to destroy 

 the physiological activity of vitamines; at least, at higher tem- 

 perature. The behavior of vitamines to acids and alkalies is of 



