FOOD VALUE OF ACORNS. 339 
Walter C. Blasdale at the University of California, showed that it con- 
tained no arsenic nor any other interesting ingredient, except the 
hydrated red oxide of iron, which was readily extracted with hydro- 
chloric acid, and was present to the extent of 10 per cent by weight. 
Experiments made by Dr. W. D. Bigelow, of the Division of Chemistry, 
and by myself, showed that acorn meal containing 6.63 per cent of tan- 
nic acid was made black, and at the same time sweet, by simply keeping 
it heated in the moist state at a boiling temperature, with a 1 per cent 
addition of ferric oxide for about twenty-four hours. A mixture of 
tannic acid and oxide of iron also turned black after exposure to the 
same treatment. 
less bread may be accounted for by the use of an acorn containing less 
tannin, or by assuming that the meal was more thoroughly washed, 
An analysis made by Charles D. Woods, director of the Maine Experi- 
ment Station, of a sample of bread made without clay from the acorns 
of the valley white oak (Quercus /obata) showed that, while the 
unleached meal contained 6.63 per cent of tannin, the bread itself con- 
tained only a trace. Professor Woods’s analyses of the acorn meal 
and bread are given by percentages in the accompanying table: ! 
The absence of disagreeable properties in the clay- 
Composition of meal from the acorns of the valley white oak (Quercus lobata) with the 
bread made from it. 
| | 7 
otal car. Food value 
Labora- Refuse, Water, Protein, Fat. bohy- | Ash. | per pound 
tory No, | drates. | | deter- 
| “ee ; mined, 
__ _ —| _ —— a 
Acorn meal........ | 6184 ool. 8.7 | 5.7 18.6 65.0 | 2.0 | 2,180 
Acorn bread ....... 6185 )....222... 60.3 2.2 9.9 27.0 | | 1, 008 
| | | | 
All of the processes as above described are the more interesting 
because they are undoubtedly wholly original with the 
California. For untold centuries they have been thus using a crop 
which is particularly abundant throughout California, and of which 
little use is made by the white people of to-day, other than as a means 
of fattening hogs. These animals are commonly allowed to run wild 
through the forest the whole year round, and are slaughtered only in 
late autumn, when they are in splendid condition tor the market. 
This is « good practical illustration of the food value of acorns to 
hogs. Let us see how experimental results and popular usage else- 
where emphasize this value, 
An inspection of the above table and a further comparison of figures, 
published in Professor Wood’s bulletin above referred to, show that 
the white-oak acorn (California), which is probably an average for 
many kinds, is comparatively rich in its contents of carbohydrates and 
especially fat. Very few nuts contain so much of the former, and the 
'Maine Agr. Expt. Station, Bul. 54, pp. 79,80. 1899. Also in letter to author. 
aborigines of 
