THE STARCH EQUIVALENT THEORY. 



By J. ALAN MlintAV, H.Sc. 

 (University College, Reading.) 



The account <;iveii by Wood and Yule of their investigation of the 

 records of British Feeding Trials and the Starch Equivalent Theory 

 in part 2 vol. vi of this Journal is a valuable and timely paper. It 

 contains abundant material for reflection. Consideration of the data 

 suggests that there is room for doubt in regard to the conclusions 

 for which a claim to " certainty" has been advanced. It is not, however, 

 the immediate purpose of this article to discuss these conclusions — 

 though incidentally certain points in the investigation come under 

 review — but rather to discern, as far as possible, the direction in which 

 the methods and arguments employed lead, and more particularly 

 what is their bearing on the starch equivalent theory as a practical 

 system. 



In their opening remarks Wood and Yule state that "starch equiva- 

 lent for this purpose (maintenance) is reckoned by the formula : starch 

 equivalent — digestible protein x 1-25 + digestible fat x 2-3 + amides 

 X 0-6 + digestible carbohydrates + digestible fibre. The generally 

 accepted maintenance ration for a 1000 lb. ox on this basis is 6-35 lb. 

 of starch e(|uivalent which includes 0-() lb. of digestible protein." The 

 author is not concerned to deny these statements but he desires to 

 emphasise the fact that this fornnila is not Kellner's formula and that 

 this estimate of the animal's requirements is not Kellner's estimate. 



The formula differs from that of Kellner^ in two respects. In the 

 latter the protein is multiplied by 0-91 instead of 1-25, and a further 

 correction which varies according to the estimated percentage value 

 for fattening of each food is also made. The formula given by Wood 

 and Yule is, as stated, intendcil to determine the value of the foods 



' The ScicHlific Feeding of Anirnah. p. 355 



