124 
of manganese alone, lucerne laccase alone, and a mixture of manganese 
and laccase, thus: 
Oxy- 
gen ab- 
sorbed. 
c. c. 
1. Manganese alone 
0.3 
2. Lucerne laccase alone 
.2 
3. Laccase 4- manganese 
6.3 
In other words, the effect of the manganese on laccase poor in this 
constituent was to increase the oxygen absorption twenty-five times. 
Other metals, such as iron, aluminium, cerium, zinc, copper, calcium, 
magnesium, and potassium, were found to be incapable of increasing 
the oxidizing power of laccase. 
He therefore arrived at the conclusion that the oxidizing ferments 
as we ordinarily recognize them consist in reality of two portions, 
one organic and very unstable with which we associate those prop- 
erties usually characteristic of the ferments as a class, and a second 
portion, which might be called the co-ferment, mineral or organic in 
its nature, and which with the first substance forms the really active 
system. Bertrand ( S9 ) therefore is disposed to regard manganese as 
the co-ferment of laccase, just as calcium is the co-ferment of pectase, 
and hydrochloric acid the co-ferment of pepsin. 
In a later communication Bertrand ( 56 ’ 57 ) proved that various 
manganese salts can bring about the oxidation of various oxidizable 
substances, such as hydroquinon, etc., in the air, and that the quan- 
tity of oxygen absorbed varies with the nature of the manganese salt 
employed, being greater with the manganese salts of the organic 
acids. The several amounts of oxygen absorbed by hydroquinon in 
the presence of various manganese salts are shown in the following 
table: 
Salt of manganese. 
Oxygen 
absorbed. 
Salt of manganese. 
Oxygen 
absorbed. 
Nitrate 
c. c. 
L. 5 
Acetate 
c. c. 
15.7 
Sulfate 
1.6 
Salicylate 
16.3 
Chloride 
1.8 
Lactate 
17.6 
Formate 
7.4 
Gluconate 
21.6 
Benzoate 
15.3 
Succinate 
22.1 
It would seem, therefore, that those manganese salts which are 
most easily hydrolyzable are the most efficient oxygen carriers. 
According to Bertrand, therefore, when a manganese salt finds itself 
in contact with water it hydrolyzes in the sense of the equation — 
R"Mn + H 2 0 = R"H 2 + MnO. 
