oenoxidase resembles laccase. It is worthy of note in this connec- 
tion, however, that, according to Legatu( 259 ), the disease of wine 
ordinarily ascribed to oenoxidase is in reality due primarily to the 
presence of ferrous salts in quantities above the normal. These are 
oxidized to ferric salts and then precipitated by the tannin, the pre- 
cipitate carrying down the coloring matter of the wine. Accord- 
ing to this author the only part played by the oenoxidase is that it 
assists in the rapid oxidation of the ferrous salts, and hence may 
participate to that extent in accomplishing the changes already 
described. 
MALOXIDASE (APPLE OXIDASE). 
\ 
The color changes occurring in fruits like the apple, pear, peach, 
etc., as a result of a wound or cut in the fruit or an abrasion of the 
skin are familiar to everyone. It is also known that no such changes 
of color occur if the fruit be previously heated to about the tempera- 
ture of boiling water. The effect of heat in preventing these changes 
is also seen to good advantage in various sorts of artificially and 
naturally dried fruits, especially dried apples. Apples which have 
been dried in the sun by natural processes are brown in color in con- 
sequence of the oxidation of tannin by an oxidizing ferment, maloxi- 
dase, contained in the fruit {see Lindet ( 271 > 272 )). On the other hand, 
evaporated apples which have been dried artificially at higher tem- 
peratures, and in some instances even exposed to the action of sulfur 
dioxide, are white, for the reason that the oxidase has been destroyed. 
The juice of the apple has been found to blue guaiacum and to oxidize 
hydroquinone and pyrogallol. In this connection it has been pointed 
out by Kastle and Shedd ( 247 ) that those vegetable tissues which 
readily oxidize guaiacum and phenolphthalin rapidly turn brown or 
reddish in color when their freshly cut surfaces are exposed to the 
air, whereas the tissues of those plants which do not oxidize these 
reagents do not turn brown or red on exposure to the air. In other 
words, the oxidases present in the raw fruit are responsible for both 
phenomena. 
According to Lindet ( 271} 272 ) the oxidase of the apple and the 
tannin upon which it acts are stored in different cells, and hence it 
is only when these are brought together by actual rupture of the cells 
that we have those color changes occurring which are characteristic 
of the bruised or macerated fruit. On the other hand, Kastle and 
Loevenhart ( 244 ) have pointed out that, on the assumption that the 
oxidizing ferments are of the nature of peroxides, the oxidase (per- 
oxide) is not present as such in the intact cell, but only its precursor, 
viz., an autoxidizable substance which, when it comes into contact 
with the air through the rupture of the tissue or cell, unites with the 
oxygen to produce the peroxide or the so-called oxidizing ferment. 
