1914] KELLEY—FUNCTION OF MANGANESE 272 
influence of excessive manganese. While the oxidases generally 
contain manganese as a normal constituent, or at least manganese 
is closely associated with the oxidases, and at the same time their 
oxygen-carrying power is accelerated by the presence of man- 
ganese salts, the foregoing investigations show that there is no 
correlation between the phenomenon of chlorosis in pineapples 
and the activity of the oxidizing enzymes. The decomposition 
of chlorophyll in this case, therefore, is not due to excessive auto- 
oxidation. This does not imply, however, that accelerated auto- 
oxidation in plants is without effect. 
From the ash analyses it was found that manganese was 
absorbed in considerable quantities, and in nearly every instance 
was greater in the plants from manganiferous soil. These analyses 
also show that a disturbance in the mineral balance takes place. 
The percentage of lime is increased, while the percentage of mag- 
nesia and phosphoric acid is decreased. Some of the plants ana- 
lyzed showed a markedly toxic effect from the manganese, while 
others appeared to be unaffected; but in practically every instance 
a modification of the mineral balance was observed, and this was 
found to follow the same direction in all species. The ratio of 
absorbed lime to the absorbed magnesia was increased under the 
influence of manganese, regardless of whether the plant showed a 
toxic effect or not. 
It is claimed by Loew (16) and others that various plants are 
affected differently by different ratios of lime to magnesia; certain 
species of plants vegetate most advantageously when the ratio is 
one to one; whereas still other species grow best when the ratio 
's one to three, etc. In the publications dealing with this subject, 
however, mention is usually made of the effects produced upon the 
appearance of plants, while but few ash analyses have been made 
'n this connection. From the data at hand, however, it appears 
that where the physiological balance between lime and magnesia 
Is disturbed, a corresponding influence is brought about in the com- 
Position of the ash. 
Under the influence of manganese, plants automatically modify 
themselves in regard to the absorption of these two elements, and, 
4S 1s believed, it is not so much the absolute amount of calcium and 
