i 4 6 W or maid. — ‘ Brown Rot ’ Diseases of Fruit Trees . II. 
gave no oxidase reaction in the culture grown at the lower temperature and 
only a very faint reaction in the one at the higher. 
In this and subsequent experiments it was generally found that the 
colour reaction in the test-tubes reached its greatest intensity in 2 to 3 
hours, after which the colour gradually faded, but often a trace remained 
after 24 hours. 
Cultures were also grown in flasks containing 200 c.c. of the apple 
extract, kept at room temperature, so that portions of the culture medium 
could be removed at intervals of a few days and subjected to the oxidase test. 
The strains used in this experiment were : 
A. The apple Blossom Wilt strain used in the preceding experiment. 
B. The plum Wither Tip strain used in the preceding experiment. 
U 
Two other Wither Tip strains. 
C. 
D. 
E. Strain of Monilia obtained from America. 
By means of a sterile pipette 10 c.c. of the culture medium were 
removed from each flask at intervals of 9, 15, 37, and 58 days from the time 
the cultures were started, and the guaiacum test applied. The maximum 
colour change given by the five strains was as follows : 
Reaction to Guaiacum Test. 
Age of culture. A . 
9 days pale blue 
15 days „ „ 
37 days deep blue 
58 days rather pale blue 
B. C. 
no change no change 
very pale blue ,, 
)> » 
deep blue very pale blue 
D. E. 
no change deep blue 
„ very deep blue 
>’ tt 
very pale blue rather pale blue 
The results show that although the plum strains are capable of secret- 
ing the oxidase into the culture medium, the enzyme is set free far more 
readily by the apple strain and the American form of Monilia during the 
period of vigorous growth. 
The colour of the culture medium (apple extract) in which the fungi 
had been growing for some time was generally darker than before inocula- 
tion, and the depth of colour was correlated with the intensity of the 
oxidase reaction given by the liquid. Thus the liquid of the cultures of the 
apple strains and of the American form of Monilia was invariably darker 
than those of the plum strains, and proved to give a more intense reaction 
to the oxidase test. 
Experiments carried out with the object of identifying the oxidase 
showed that it had no action on tyrosin or hydroquinone ; it could not 
therefore be referred either to tyrosinase or laccase, two oxidases which 
have been found in fungi. On the other hand it rapidly produces a brown- 
ish yellow colour in solutions of tannic acid, gallic acid, and pyrogallic acid. 
In this respect it behaves as the enzyme oenoxydase found by Martinand 
(16, 17) in ripe grapes and ascertained by Laborde ( 14 ) to be secreted by 
