194 
Journal of Agricultural Research 
Vol. XXX, No. 2 
In a stillborn child there were 26.1 
mg. of copper and 73.9 mg. of zinc 
per kilogram in the liver. 
The author (8, 9, 10, 11) has shown 
that manganese is an essential element 
in the growth of autotrophic plants 
and functions in the synthesis of 
chlorophyll, for when this element is 
carefully excluded from sand culture 
experiments plants do not synthesize 
chlorophyll and, consequently, make 
very little growth. 
EXPERIMENTAL DATA 
SOILS 
Preliminary experiments on a few 
virgin soils from the more impor¬ 
tant soil areas of Kentucky show 
that they contain amounts of the 
elements arsenic, copper, antimony, 
manganese, zinc, nickel, cobalt, barium, 
and strontium large enough for esti¬ 
mation by the usual methods of quali¬ 
tative chemical analysis applied to the 
hydrochloric acid extract from 1,000 
gm. of air-dried soil. The purified 
precipitates obtained in the analysis 
of the solution from one virgin soil 
gave the following quantitative re¬ 
sults in parts per million of the element 
in the air-dry soil: 3 Arsenic 10.8, 
copper 7.2, zinc 27.7, cobalt 1.5, nickel 
3.9. The presence of these elements in 
a Kentucky soil in greater quantities 
than was anticipated suggested further 
investigations as to their presence in 
certain parts of plants and animals 
which had received their sustenance 
from the soil in which these elements 
occur. 
PLANT SUBSTANCES 
Thus far the foliage and seeds of a few 
of the more important farm crops have 
been examined for some of the so-called 
nonessential elements. The ash result¬ 
ing from the incineration of 1,500 gm. of 
air-dry corn silage was digested in hot 
20 per cent hydrochloric acid. The 
insoluble material was filtered and 
washed free of chlorides. The hydro¬ 
chloric acid solution of the ash was 
examined by the usual procedure of 
qualitative chemical analyses and the 
following elements were found: Arsenic, 
appreciable; lead, trace; copper, ap¬ 
preciable; manganese, considerable; 
zinc, appreciable; nickel, trace; barium 
and strontium, appreciable. 
Samples of the following materials 
were analyzed: 
Kentucky bluegrass (Poa praten - 
sis ): A clean, hand-picked sample of 
the fresh blades which were about 6 to 
10 inches in length. The blades of 
grass were free from soil or other 
extraneous matter. 
Soybean leaves: Fresh leaves were 
hand picked from the upper half of 
plants about 3 to 4 feet tall, growing 
in the field. The leaves were free from 
soil or other visible extraneous matter. 
Soybean seeds: The seeds were clean 
and mature, and were grown on the 
same farm and the same type of soil 
as the soybean leaves but not on the 
same plants. 
Wheat bran: A sample of wheat bran 
from a red winter wheat was obtained 
at a flour mill. The bran was freed 
from the germs and small particles of 
bran by shaking in a 20-mesh sieve and 
selecting the larger flakes of bran that 
remained on the sieve for the analysis. 
Wheat germs: This material was not 
absolutely pure wheat germs but was a 
representative sample of the material 
designated as wheat germs by the 
miller. It contained small particles of 
bran and some flour. Perhaps the 
germs formed as much as 70 per cent 
of the mixture. 
Patent flour: The sample represented 
the highest grade of patent flour and 
was produced at the same mill at which 
the wheat bran and wheat germs were 
obtained. 
Corn germs: The corn germs were 
dissected by hand from sound, mature 
grains of white Hickory King corn, 
which had grown on the Kentucky 
Agricultural Experiment Station farm, 
at Lexington. 
Corn endosperm: The remaining part 
of the corn grains was used from which 
the germs had been cut out by hand 
with a small gouge. 
Rice polishings: A sample of the 
commercial material containing the 
pericarp and germ of the rice grain, 
removed from the grain in the process 
of polishing. 
Polished white rice: The commercial 
product from which the pericarp and 
germ have been removed in the process 
of polishing was selected. 
It is evident from the data in Table I 
that when the cereals, wheat, corn, and 
rice are highly milled by modern pro¬ 
cesses, the finished products, patent 
flour, degermed corn meal, and pol¬ 
ished rice, are practically freed from 
copper, manganese, zinc, and iron. It 
is interesting to note that the germs of 
wheat and corn are relatively rich in 
copper, manganese, and zinc, thus 
showing a close association of these 
elements with the vital part of these 
grains. 
J Methods of estimation (U): Arsenic, Gutzeit Method, page 46; Copper, ammonia method, page 
167; Zinc, precipitated as sulphide in CHsCOOH and weighed as sulphate, p. 479; Nickel, dimethyl- 
glyoxime method, p. 287; Cobalt, nitroso-beta-naDhthol method, p 143 
