152 Wormald . — ‘ Brown Rot * Diseases of Fruit Trees. If. 
Experiment 8. 
Strains grown in Coons' Solution. 
A. From an apple spur. 
B. From a mummied cherry. 
C. From a plum twig affected with the ‘ Wither Tip’ disease. 
D. A strain from America (Oregon). 
E. Another strain from America (Ontario). 
(a) Guaiacum Emulsion as Reagent. 
Results in tubes 1 and 2. 
Time. 
A. 
B. 
C. 
d: 
E. 
2 hrs. 
slight bluish tint 
no change 
no change 
no change 
pearl blue 
4 hrs. 
deeper than pearl blue 
ditto 
ditto 
ditto 
clear Windsor blue 
8 hrs. 
deeper than pale Windsor blue 
ditto 
ditto 
ditto 
ditto 
24 hrs. 
light Windsor blue 
ditto 
ditto 
pearl blue 
ditto 
(b) 2 per cent. Pyrogallic Acid as Reagent. 
Time. A. B. C. 
D. E. 
2 hrs. very pale yellow no change no change 
4 hrs. pale yellow ditto ditto 
8 hrs. ditto ditto ditto 
24 hrs. bright yellow ditto very pale yellow 
no change very pale 
very pale yellow pale yellow 
ditto ditto 
bright yellow deep yellow 
. I 
In Coons’ solution the growth of the strains was comparatively feeble, 
the diameter of the mycelial discs at the end of seven days being only about 
half that of the cultures of the same age in the fruit extracts, and the hyphae 
were less densely interwoven. The oxidizing reaction of the cultures was 
more gradual than in the other experiments of the series, and the pyrogallic 
acid proved to be the more sensitive of the two reagents. 
The dark coloration developed in the fruit extracts when certain 
strains of Monilia cinerea are growing in them is, in all probability, due to 
the fungus. That the presence of tannins is not a factor necessary for the 
secretion of the oxidase is shown by the cultures grown in Coons’ solution, 
a medium consisting of inorganic salts, asparagin, and glucose. 
It was found in every experiment that the strains of Monilia cinerea 
from apple trees produced the oxidase far more readily than those from 
other sources, with the exception of the American strains, which appear to 
belong to a distinct variety, if not species. This is correlated with their 
power of infecting apple flowers ; five of the strains which have given no 
oxidase reaction, or a very feeble one, have been used in the inoculation 
experiments on apple flowers, and all failed to produce the blossom wilt 
condition which is typical of infection by the apple strains. 
