126 
active oxidase than plants which have onl} r small percentages of this 
element. 
On the other hand, oxidases have been obtained which contain no 
manganese. Thus Sarthou ( 357,359 ) found the oxidase of S chirms 
molle to contain iron, calcium, and sodium, but no manganese; ac- 
cording to this author the oxidizing power of this oxidase is propor- 
tional to its iron content. Yadam ( 438,439 ) found iron but no man- 
ganese in the ash of an oxidase from hellebore. According to Stoeck- 
lin ( 412 ), manganese is not present in the ash of the oxidase from horse- 
radish. 
It is evident, therefore, that certain metals, such as iron, manga- 
nese, and copper, one or more of them, enter into the composition of 
the oxygen carriers present in the living organism as essential ingre- 
dients. In this connection it is interesting to note that small amounts 
of manganese greatly accelerate a number of chemical processes. 
Thus according to Yilliers ( 441 ) if one boils equal volumes of a satu- 
rated solution of oxalic acid and hydrochloric acid containing 25 per 
cent of HC1, and nitric acid equally dilute, there is not produced 
any disengagement of gas, even after a long time; on the other hand, 
if one adds to the solution a trace of a manganese salt the action 
develops instantly and there is produced a regular disengagement of 
carbon dioxide and nitrogen. This author has compared the action 
of a manganese salt to that of a mineral ferment ( ferments mineraux). 
In another communication he ( 442 ) describes the use of small amounts 
of a manganese salt in the destruction of organic matter in toxico- 
logical analysis. Gigon and Rosenberg ( 193 ) have observed that the 
presence of small amounts of manganous or ferrous sulfate increases 
very markedly the digestion of starch by the diastatic blood ferment 
and by the pancreatic diastase. 
Attempts have been made, therefore, to prepare artificial oxidases 
by means of certain manganese and iron compounds, and some ob- 
servers have pointed out various analogies existing between certain 
metallic salts and the oxidases. Thus according to Trillat ( 436 ) when 
a small quantity of manganese chloride is added to a dilute solution 
of fresh egg albumin (3 parts to 100 of water) and the solution made 
faintly alkaline with caustic soda or potash there is produced a solu- 
tion which in the raw state rapidly turns brown in the air, the change 
of color beginning on the upper surface of the liquid. In contact 
with the air this solution has been found to blue guaiacum and to 
oxidize hydroquinone with the production of quinone, and pyrogallic 
acid to purpurogallin. Thus with a solution of alkali alone a given 
quantity of pyrogallic acid gave 0.102 gram of purpurogallin, whereas 
under the same conditions the albuminous solution containing man- 
ganese gave 0.617 gram of purpurogallin. It was observed, further, 
