I<i4 Maiiihnance Jiallons aiid Slarrli I'Jtiiiinili iils 



dietaries, and consequently the results obtained in ordinary fecdinj; 

 trials will rarely be affected by lac'k of these factors. 



Two papers of importance on the subject of starch cc|uivalents 

 have recently a])pcarcd, tliat of Wood and Yule*, in which an attempt 

 has been made to explain tiie discrepancies existinj; between the German 

 figures and the results obtained in Kni^lish fccdinj; practice; and the 

 more recent jiaper of Murray''', which not oidy favours total abolition 

 of the Kellncr system, but also criticises the accuracy of the results 

 stated by Wood and Yule. The present paper has, therefore, been 

 written with a view to dearinp up the jioints dealt with by Murray 

 in his paper, and criticism of Murray's views has consequently been 

 confined to those points which bear directly on the subject under 

 discussion. 



In the first portion of the ])aper. Wood and \"ule are criticised for 

 suggesting the necessity of distinguishing between "starch equivalent 

 for maintenance" and " starch equivalent for production." Recognising 

 the difTercnce between the thermic and dynamic values of foods, and 

 the fact that within reasonable limits the total digestible thermic 

 energy of a food is available for maintenance, AVood and Vule give 

 two diflerent formulae to be a])])lied according as the food is intended 

 for maintenance })ur])oses or fattening ])ur]ioses. In doing so they 

 thus render easy a distinction between the thermic and dvnamic value 

 of a food, and one of Murray's most serious objections to the Krllnci- 

 system disappears. It may be as well here to define clearly what 

 Kellncr intended by his system. Kellner aimed at giving a measure 

 of the availal)lc energy of the excess of any ration over the maintenance 

 ration by measuring the amount of fat produced compared with the 

 amount of fat produced by an equal quantity of starch. The available 

 energy once determined and stated as starch equivalent may be readily 

 calculated to work production, milk production, or any other purpose. 

 The starch equivalents so determined were intended to be used solely 

 for estimating the relative fattening capacities of various foods, and 

 were not intended to be applied indiscriminately for the estimation 

 of maintenance and also for the production of fat. The endeavour 

 to do .so naturally led to much confusion of thought as to the exact 

 nu'iining of "starch e(|uivalent," and the attempt to interpret main- 

 tenance requirement in terms of "starch e(|uivalent," i.e. "starch 

 e(]uivalent for fat production," caused even Kellner to confuse the 



' Wood and Yule, .loiini. nf .iijrir. Sei. 6, p. 2:t:!. 

 * Murray, ibid. 7, p. 154. 



