150 Wormald. — Brown Rot ’ Diseases of Fruit Trees . II. 
All the tubes at first showed a very faint yellowish tint owing to the 
colouring matter present in the culture medium. Tube No. 6 of each 
strain showed a very gradual deepening of the tint due to the slow oxida- 
tion of the pyrogallic acid, which normally darkens when in solution in 
contact with the air, but after 24 hours all the four tubes were still a very 
pale yellow and the tint was but slightly deeper after 48 hours. 
The following table gives a resume of the results obtained for all the 
strains of Monilia tested in this series of experiments. The numbers 
indicate the maximum colour change which developed in each case ; the 
values of these numbers in the guaiacum test are as follows : 
1. indicates a faint bluish tint. 
2. corresponds to pearl blue. 
3. „ pale Windsor blue. 
4. „ light Windsor blue. 
5. „ clear Windsor blue. 
The colour changes in the pyrogallic acid could not be so readily 
defined, the transparent liquids not being suitable for use with the colour 
chart. 1, however, indicates a very slight yellowing just discernible when 
the tubes were carefully examined side by side with the control (heated) 
tube, while 5 denotes a deep brownish yellow. In Expt. 1 tannic acid was 
used instead of pyrogallic acid. 
As in the case of the apple extract, it was found in these experiments 
that in general the darker the culture medium (extract of peaches) had 
become under the action of the particular strain growing in it, the more 
intense was the oxidase reaction it gave. The cultures in Coons’ solution, 
however, all remained colourless, and as the results obtained in the tests, 
though essentially confirming those obtained with the fruit extracts, showed 
some variation in detail from the rest of the series, the results are given 
fully. 
