PRODUCTION AND CONSERVATION OF FATS AND OILS. 31 
in the United States, in time the sunflower may be numbered among 
our oil-producing plants, since it is possible to use its oil to good 
advantage for both food and technical purposes. 
Cacao butter is practically the only naturally hard vegetable fat 
produced in this country. It is obtained as a by-product in the manu- 
facture of beverage cocoa. To make chocolate, the cacao bean is 
roasted, ground, and degerminated in the grinding process. Cocoa 
is obtained by pressing the chocolate and extracting part of the oil 
in hydraulic or screw presses. Before the war, the demand for cacao 
butter in this country was so great that it could not be supplied by 
our domestic manufacturers. Our average annual imports of cacao 
butter and its substitutes for the three prewar years of over 4,000,000 
pounds dropped in 1917 to 166,000 pounds, and in that year we 
exported 551,000 pounds. Cacao butter is used largely in making 
confectionery. It owes its importance in this industry to the fact 
that it is necessary to add a certain amount of this fat to chocolate 
before the sugar in sweetened chocolate will dissolve freely. Since 
the scarcity of sugar has increased the price and decreased the pro- 
duction of confectionery, much less cacao butter is needed now than 
a few years ago. Consequently, cacao butter, formerly the most 
important article made by the cacao manufacturer, has . become a 
by-product, and is one of the very few fats which have not materially 
increased in price. Cacao butter is also an important ingredient in 
certain pharmaceutical preparations, as salves, and attempts have 
been made to use it in the manufacture of margarines. 
The United States is as yet dependent upon the Orient for its 
supply of tung oil, known here as Chinese nut oil or China wood oil, 
which is pressed by rather crude methods from the tung nut, Aleurites 
cordata. A f&w experimental plantings of this tree have been made 
in the far South, but they have not as yet yielded any commercial 
quantity of oil. Although the importation of tung oil into this 
country is nothing new, the quantity we bring in has been steadily 
increasing, until in 1916 nearly 57,650,000 pounds were received, as 
compared with the average 1912-1914 importations of 42,000,000 
pounds annually. In 1917 the imports dropped off to 41,190,000 
pounds. Since this oil is more important than ever just now, on 
account of the increased demand for rosin varnishes, some steps 
must be taken to increase our supply. Tung oil is poisonous, or at 
least so strongly laxative that it is not used in foods, and so far as 
is now known it can not be sufficiently refined to form an edible 
product. It is the best substitute we have for linseed oil in paints 
and especially varnishes. In fact, when rosin is used instead of the 
foreign varnish "gums," the tung oil is superior to linseed oil. The 
so-called "spar varnishes/' which do not discolor when wet, are 
largely tung oil rosin preparations. For the waterproofing of our 
