Palmitic Acid, Glyceryl Palmitate, Ethyl Palmitate. 169 



Two dogs were used for each experiment. The fats em- 

 ployed were added to a basal ration of lean beef, cracker crumbs, 

 and agar. The ethyl palmitate used was neutral ; melting point 

 24°; saponification number 198 (theoretical 197.6). Glycerol 

 palmitate was prepared by heating glycerol and palmitic acid 

 together according to the method of Ellis and Rabinovitz. 1 It was 

 a hard solid with a melting point of about 6o°. Feces fatty acids 

 were determined by the method of Gephart and Csonka. 2 Utili- 

 zation was as follows: 





Dog »i 

 Per Cent. 



Dog 2, 

 Per Cent. 



Amount Fed per Day, 

 Grams. 



Lard 



95-8 



95-3 



40 



Ethyl palmitate 



56.8 



48.2 



40 



Glyceryl palmitate 



91.7 



93-1 



40 



Palmitic acid 



81.2 



79.I 



40 



The ether extract of the feces resulting from feeding ethyl pal- 

 mitate contained 79.4 per cent, unchanged ester, identified by its 

 melting point, and 20.6 per cent, free palmitic acid. 0.9 per cent, 

 palmitic acid combined as soaps was found. 



The poor absorption of ethyl palmitate we think due to a slow 

 hydrolysis as indicated by the large amount of unsplit ester re- 

 covered in the feces. Frank 3 has reported a utilization of 75 

 per cent, for ethyl palmitate; however, the dogs used in his 

 experiments were purged by the large amounts fed and a loss of 

 feces might have resulted in spite of care in collection. The good 

 utilization of glyceryl palmitate is in marked contrast to the poor 

 digestibility of tristearin (9 to 14 per cent.) reported by Arn- 

 schinck. 3 It may be worthy of note in this connection that Frank 4 

 found ethyl stearate utilized to a much less extent than ethyl 

 palmitate, 12 and 75 per cent, respectively. The utilization of 

 glyceryl palmitate is perhaps better than would be expected for 

 such a high melting fat. Mutton tallow, however, having a 

 melting point of 49 0 is well utilized by dogs (93 per cent.) as found 

 by Arnschink and others. 



1 Ellis and Rabinovitz, J. Ind. and Eng. Chem., 8, 1 105, 1916. 



2 Gephart, F. C. and Csonka, F. A., J. Biol. Chem., 19, 521, 1914. 



3 Arnschink, L., Zeitschr. f. Biol., 26, 434, 1890. 



4 Frank, O., Zeitschr. f. Biol., 36, 568, 1898. 



