DIGESTIBILITY OF SOME BY-PKODUCT OILS. 3 



cient quantities to obviate long hauls it apparently was necessary to 

 find some use for the entire pit. 



The residue, commercially known as press cake, remaining after 

 the expression of oil from peach, apricot, and cherry kernels, has 

 much the same composition and nutritive value for stock feeding as 

 the press cakes obtained from such oil seeds as soy bean, linseed, 

 peanut, coconut, and cotton seed. Until very recently, however, the 

 outer woody portion of the pits seemed to be of little value except 

 for fuel purposes. Experimental tests and large-scale use of the 

 carbon produced from the woody portion of fruit pits showed quite 

 conclusively that this carbon is valuable, especially for the manu- 

 facture of gas masks. Thus, with a possible commercial demand 

 existing for all portions of the fruit pits, it seemed desirable to give 

 consideration to the utilization of these by-products. 



While the oils obtainable from waste pits and seeds are satisfactory 

 for a variety of technical purposes, it is of course evident that if they 

 can be commercially prepared so that they are satisfactory for such 

 purposes they should be available for food. Especially is this true at 

 the present when a world-wide shortage of fats and oils exists. Ac- 

 cordingly, laboratory studies of the expression of oils from various 

 kernels were made. The results of these studies showed that if care 

 was observed both in the preparation of the pits and in the expression 

 of oil from them a high-grade edible oil could be obtained. 



If the peach, apricot, and cherry pits were allowed to stand for 

 any length of time in the moist condition in which they were re- 

 moved from the fruits, fermentation developed and the oil which 

 was obtained was usually not suited for edible purposes. On the 

 other hand, it was found in laboratory procedure that if the peach, 

 apricot, and cherry kernels were dried, ground, and expressed by 

 hydraulic pressure (i. e., "cold pressed"), the oils obtained were 

 perfectly satisfactory for table purposes without any refining other 

 than merely filtering. The peach, apricot, and cherry oils prepared 

 in this laboratory by the above procedure were of a bland flavor, and 

 when mixed with vinegar and condiments made excellent French 

 dressing. In view of these findings it was decided to determine how 

 well these oils are tolerated by the human body and to what extent 

 they are digested. Accordingly, a supply of a number of oils which 

 may be obtained from the by-products of the canning industry was 

 secured, and the coefficients of digestibility were determined in the 

 same manner as those of the other edible oils reported in previous 

 publications. 



DIGESTION EXPERIMENTS WITH MEN. 



The subjects who assisted with this investigation were men in good 

 health, whose ages ranged from 20 to 40 years. In order that the 



