220 Alleged Excretion of Creatine in Carbohydrate Starvation. 



and creatine must be inaccurate, unless the precaution is taken of removing 

 the aceto-acetic acid from the urine. 



Conclusions. 



1. The presence of aceto-acetic acid always causes an error in the estimation 

 of creatinine and the error increases with increasing amounts of aceto-acetic 

 acid. As the result of this error the estimation of creatinine will be too low. 

 This error is not eliminated if the diluted urine is allowed to stand for 

 varying lengths of time before making the readings. 



2. The aceto-acetic acid is removed in the estimation of creatinine + 

 creatine and does not cause any error. 



3. As the creatinine figure is too low and the creatinine + creatine figure is 

 correct, it will appear that creatine has been excreted. 



4. Acetone and /3-oxybutyric acid, if present in amounts comparable to 

 those which usually occur in urine, produce practically no error in the 

 estimation of creatinine. 



5. A simple and reliable method has been devised for removing aceto- 

 acetic acid, preliminary to the estimation of creatinine. 



6. In our experiments a carbohydrate-free diet did not cause the excretion 

 of any creatine. 



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