INTRODUCTORY 9 



stances present in the body in small amounts, but 

 which nevertheless exert powerful effects such as 

 the enzymes or ferments. 



Vitamines, as every reader of the press must 

 know by this time, are unknown factors in food, 

 probably present in amounts that defy weighing 

 by the ordinary chemical balance. They are neces- 

 sary for a continuation of the life cycle. As I have 

 said elsewhere, 1 without vitamines there can be no 

 life. 



To what extent are we justified in comparing 

 vitamines with hormones? As we have indicated, 

 both are present in minute quantity, and a small 

 quantity seems to go a long way. Both are there- 

 fore "catalytic" in their action; that is to say, 

 they accelerate or hasten chemical action, without 

 themselves undergoing any permanent change. 



There are one or two direct clinical observations 

 that are of interest also. Professor Butcher, of the 

 Pennsylvania State College, has performed a num- 

 ber of experiments which show that thyroxin, the 

 thyroid hormone, has anti-neuritic properties; 

 which means that it, like yeast, for example, can 

 cure birds suffering from polyneuritis, a disease 

 first shown by Funk to be due to a lack of one of 

 the vitamines. 2 If this is so, thyroxin has vitamine- 

 like characteristics. 



*See the author's book, Vitamines: Essential Food Factors. 

 New York, E. P. Button & Company, 1921. 



J See the chapter on Beriberi in the author's book on Vitaminea. 



