210 Messrs. G. Graham and E. P. Poulton. The Alleged 



factor, as it might be the cause of the colour change. However, the addition 

 of alcohol to urine in amounts which correspond to those added with the 

 sodium aceto-acetate did not produce any alteration at all in the colour. 

 The possibility still remained that it was the mixture of the alcohol with 

 the sodium aceto-acetate which was responsible for the change in colour. 

 There is no means of directly disproving this hypothesis, as the alcohol 

 cannot be removed from the sodium aceto-acetate solution without destroying 

 the salt. There is, however, indirect proof that this is not the case, as will 

 be shown in the following paragraphs. 



Aceto-acetic acid is excreted in the urine during carbohydrate starvation. 

 As will be shown later on, the aceto-acetic acid can easily be removed from 

 the urine without breaking down creatinine or creatine, and this procedure 

 was followed in three diet experiments which will be described in detail 

 later on. The urine which contained aceto-acetic acid had apparently less 

 creatinine in it than the urine from which the aceto-acetic acid had been 

 removed. Thus on the 2nd day Experiment I, a concentration of aceto- 

 acetic acid of 0-065 per cent., caused an error in the creatinine figure of 

 017 grm. per 100 c.c, and a concentration of aceto-acetic acid of - 081 per 

 cent, on the third day caused an error in the creatine of 028 grm. per 

 100 c.c. On the second and third days of Experiment II the concentration 

 of aceto-acetic acid of 0-085 and - 112 per cent, produced errors of 0'018 and 

 0-027 grm. per 100 c.c. respectively (Table III). 



Table III shows the Error caused in the Estimation of Creatinine caused by 

 the Excretion of Aceto-acetic Acid in the Urine consequent on 

 Carbohydrate Starvation. (Extracted from Tables VII-IX, pp. 217 

 and 218, of this paper.) 



Day. 



Concentration of 

 aceto-acetic acid 

 per 100 c.c. 



Error caused by 

 aceto-acetic acid 

 in determination 

 of creatinine. 



Diet, Experiment I — 



2 



0-065 



grm. per 100 c.c. 

 0-017 



3 



0-081 



0-028 



Diet, Experiment II — 

 1 



029 



0-005 



2 



-085 



018 



3 



0-112 



0-027 



Diet, Experiment III — 

 1 



036 



-01 



2 



0-072 



0-008 





