418 
Journal of Agricultural Research 
Vol. XXVII, No. 6 
Experiments conducted with many additional species of plants estab¬ 
lish the fact that manganese is an essential element for the metabolic 
processes and the normal growth of autotrophic plants. When manga¬ 
nese becomes a limiting factor in the growth of plants, one of the first 
effects to be noted is a chlorotic condition of the young leaves and buds 
as they unfold—a fact which shows that this element has a function in 
the vital processes and is necessary for the synthesis of chlorophyll. * 
The green leaves of plants are known to be an important source of vita¬ 
mins, whereas blanched or chlorotic leaves are poor in vital factors; it 
has been shown also that green leaves contain more manganese than 
any other part of the plant, thus indicating that an interrelationship 
exists between chlorophyll, vitamins, and manganese. 
MANGANESE IN THE PERICARP OF SEEDS 
Since it has been demonstrated that the vitamin in whole grain of 
wheat, barley, and rice is contained in the pericarp and the germ, an 
examination of these cereals was made to determine the amount of 
manganese in the different parts of each and to show what proportion 
is removed in the modern processes of milling. Accordingly, samples of 
rice bran, rice polishings, unpolished rice grains, and polished white 
rice grains were analyzed for manganese. The results obtained, in 
parts per million of the air-dry material, are as follows: 
Material: Manganese 
Rice bran. 350 
Rice polishings. 100 
Unpolished rice grains. 25 
Polished rice grains. 10 
From these results it is apparent that rice bran contains the largest 
quantity of manganese and the polishings contain the next largest, which 
is less than one-third of the amount found in the bran. The unpolished 
rice grains contain only one-fourteenth as much manganese as the bran 
and one-fourth as much as the polishings but two and one-half times as 
much as that found in the polished white rice. It is therefore apparent 
that in the process of polishing rice the greater part of the manganese 
is removed from the grain. It is logical to assume that the manganese 
contained in the pericarp and germ, and removed in the polishing, is 
in a different and perhaps more active combination than that contained 
in the more starchy and glutinous part of the endosperm. This assump¬ 
tion finds support in the results obtained by Eijkman (/j, p. 8-9) and 
others who have found that the addition of the pericarp of the rice 
grain or even the bran to polished white rice prevents the development 
of beriberi in experiments with animals. 
It has been shown by many investigators that the vitamin contained 
in rice bran and polishings is soluble in water, but less so in 95 per cent 
alcohol. The writer has examined the aqueous and alcoholic extracts 
from rice bran and polishings and has found that a considerable propor¬ 
tion (80 parts per million) of the manganese in each of these materials 
is soluble. The amount removed by alcohol depends upon the percent¬ 
age of water contained in the alcohol. Very small amounts of manganese 
are soluble in 95 per cent alcohol, and the amount dissolved increases as 
the percentage of water in the alcohol increases, a fact in harmony with 
the findings that the aqueous and alcoholic extracts of rice bran and 
rice polishings contain the so-called vitamins. 
