2 BULLETIN 630, U. S. DEPARTMENT OF AGRICULTURE. 
not be purchased in any considerable quantities and are little used 
in this country as such, very considerable quantities are consumed 
annually as a constitutent of the nuts in which they occur. 
Inasmuch as sufficient quantities of these nut oils could not be 
procured in the open market, a supply of good grade nuts of the 
varieties to be studied was procured and the oils were expressed under 
laboratory conditions with a hydraulic press having a capacity of 
35 tons pressure on a 6-inch plunger. All of the oils were ;; cold 
pressed " and were of excellent quality, being in such good condition 
that no refining was necessary. They were allowed to stand some hours 
in order that any suspended matter might settle and then they were fil- 
tered through one thickness of ordinary filter paper. In all instances 
the oils were of good color, without odor, and possessed a bland 
flavor ; in one or two instances more or less of the characteristic flavor 
of the nuts from which the oils were derived could be detected. Since 
they were used within a short time after they were expressed, little 
information was obtained in regard to the keeping quality of the oils. 
The press cake remaining after the oils had been expressed from 
the nuts was quite palatable though not as " rich " as the nuts, and 
rather dry if eaten alone. The characteristic flavor of the nuts was 
retained by it and was in many cases intensified. Since the press 
cake was derived from a good grade of cleaned nuts it had consider- 
able interest as a possible food material, especially in view of its 
high protein content. That obtained from several varieties of nuts 
was accordingly studied in this office from a dietetic standpoint, and 
various recipes for its use were developed. The value and possible 
uses of such press cake will be discussed in a later publication. 
In the studies of the digestibility of the 16 animal or vegetable 
fats, reported in previous bulletins, an average of eight tests was 
made with each fat; in only one case were there less than five 
experiments. Because of the limited available supply of the oils 
considered in this paper only three or four tests could be made with 
the oils studied. 
METHODS OF PROCEDURE. 
The digestion experiments with the nut oils were conducted by the 
same methods as those with the animal and vegetable fats already 
reported, the object being to maintain identical experimental condi- 
tions for each fat studied and thus to make the values obtained for 
the digestibility of the different fats directly comparable with one 
another. 
As in the earlier experiments, a blancmange, or cornstarch pud- 
ding, served as the medium for introducing the fat under considera- 
tion. The blancmange was prepared by the method outlined in a 
