i6 



FEEDING EXPERIMENTS WITH ISOLATED FOOD SUBSTANCES. 



EXPERIMENTAL PART. 

 CONTROL FEEDING. 



A somewhat detailed protocol of the metabolism experiments 

 on two of the "control" rats fed on dog biscuit and lard, as already 

 mentioned, will serve as a typical description of the conduct of all 

 our feeding trials. Rat xn and rat xiii were caged separately on 

 August 9, 1909. Fresh food-paste (see page 13) was introduced 

 daily into the food dishes in excess of the amount eaten, w r hich was 

 at first ascertained daily. The body-weights were at first deter- 

 mined every other day, as was the nitrogen of the excreta (urine and 

 faeces) . Subsequently it was found adequate to estimate the nitrogen 

 balance in weekly periods. The data thus obtained are summarized 



Table I. Summary of Data on "Control" Rat XII, fed on Dog Biscuit-Lard 



Diet for 147 Days. Daily Averages. 



