EXPERIMENTAL EXPRESSION OF THE RELATION- 

 SHIP BETWEEN THE CONTENT OF A FOOD- 

 STUFF IN ANTINEURITIC HORMONE AND THE 

 PERIOD OF HEALTHY SURVIVAL OF ANIMALS 

 UPON IT. 



By Henry Hamilton Green, D.Sc, F.C.S. 



(Abstract. 



{Printed ill Aniuial Report of the Director of Veterinary 



Research, Pretoria.) 



An extensive series of experiments uix)n pigeons is recorded, 

 on diets varying- in known fashion in regard to content in vita- 

 mine or antineuritic hormone, and an attempt is made to find 

 a simple algebraic expression to explain the data. .'V formula 

 is tentatively sugti'ested : 



K I 



6- = — 



V- X C 



Where .S" = period elapsing before onset of deficiency disease. 



V = minimum proportion of vitamine in the diet neces- 

 sary for health. 



X = proportion of vitamine actually present in the diet. 



K = proportion of vitamine reserve in the tissues of 

 the animal. 



C = the available energy value of the diet. 



It is argued that this tentative expression explains the 

 observations much better than the simple assumption that a 

 fixed daily vitamine intake is reciuired. and gives some indica- 

 tion of the length of time which may be expected to elapse before 

 onset of deficiency symptoms on any given diet is noticeable. 

 It indicates that the f|uantity of vitamine required for health is 

 not absolute. l)ut depends upon the gross energy value of the 

 diet, and suggests that the (function of vitamine is related rather 

 to the gross metabolism than to the structural requirements of 

 the animal. A considerable amount of evidence is adduced in 

 support of this expression, which, though it cannot be relied 

 u])on in any one given case, seems to fit fairly well when a large 

 number of individuals is considered, and individual idiosyncrasy 

 is ruled out. Individual variation in vitamine requirements is 

 shown to be great, and this factor renders definite proof exceed- 

 ingly difficult to obtain. The expression is therefore only pro- 

 visional, and intended as a guide in the interpretation of conflict- 

 ing data. It is held that the value for Y. is much the same in 

 the avian and in the human subject, but much lower in cattle. 



