1913] H. C. Biddle and Paul E. Howe 387 



The procedure employed in determining some variations due to 

 fasting was as follows : muscles (M. sentit endinosus and M. hiceps 

 femoris) of normal animals were analyzed for moisture, fat, phos- 

 phorus and creatine ; and, in one case, the heart was analyzed for 

 nitrogen and creatine. 



Muscles of the same kind were removed aseptically from normal 

 dogs under ether anesthesia^ and analyzed for nitrogen and creatine. 

 After a prolonged fast the corresponding muscles of the opposite 

 legs of the "operated" dogs, as well as the remaining muscles on 

 the same side, were analyzed for total nitrogen and creatine, and 

 in two cases for moisture and fat. With such a procedure the 

 changes which resulted from fasting were studied on the same 

 individual, also in fasted animals as compared with different normal 

 controls. The "operated" dogs recovered readily and the wounds 

 healed rapidly even when the fast was begun immediately after the 

 Operation. 



The analytical methods employed were as follows: Total 

 nitrogen was determined by the Kjeldahl process ; moisture by dry- 

 ing in a vacuum over sulfuric acid at room temperature ; fat by the 

 ether-extraction process, and creatine by the Folin procedure as 

 modified for meat by Emmett and Grindley.* The creatine was 

 extracted according to the methods of Grindley and Woods^ and 

 of Mellanby.^ 



The table on page 388 contains the more significant data. 



A consideration of this data shows an increase in the percentage 

 of moisture, and a decrease in the percentages of nitrogen and crea- 

 tine, in the striated muscle as a result of fasting. From the data 

 on a Single normal heart and a single fasting heart there appears 

 to have been a decrease in the nitrogen and an increase in the 

 creatine content of the fasting heart. We also note that the 

 changes which take place in the same fasting individual, as con- 

 trasted with the fasting changes when compared with different con- 

 trol animals, are approximately the same. 



'We wish to thank Dr. O. O. Stanley, of the University of Illinois, and 

 Dr. C. T. Moss, of the Michael Reese Hospital, of Chicago, Illinois, for their 

 aid in the removal of the muscles. 



* Emmett and Grindley: Jour. of Biol. Chem., igoy, iii, p. 491. 



^ Grindley and Woods : Ibid., igoö-'o;, ü, p. 309. 



' Mellanby : Jour. of PhysioL, 1908, xxxvi, p. 453. 



