WormalcL — ‘ Brown Rot 9 Diseases of Fruit Trees. II. 149 
When the cultures were seven days old the liquid was poured off into wide 
test-tubes labelled to correspond with the strains. For each strain six 
narrow tubes (1 cm. internal diam.) were prepared and numbered 1 to 6. 
Into each of Nos. 1, 2, and 3 was run (with a graduated pipette) 1 c.c. of the 
culture medium and into Nos. 4, 5, and 6 were run 2 c.c. of the medium ; the 
colour change in the pyrogallic acid not being so striking as in guaiacum 
emulsion, the larger volume was used for this reagent. Tubes 3 and 6 were 
next heated in a water-bath at ioo°C. for two minutes and allowed to cool. 
Into tubes i, 2, and 3 were now run 5 c.c. of the guaiacum emulsion and into 
4, 5, and 6 five c.c. of the 2 per cent, pyrogallic acid solution. The tubes 
were then placed in a thermostat at 25 0 C., examined from time to time, 
and the colour changes noted. In the guaiacum emulsion the change in 
colour corresponded very closely to the series of tones in Ridgway’s colour 
scheme ( 23 ) on Plate XXXV, 49" Blue, and that series was used in naming 
the colours. 
(a) Guaiacum Emulsion as Reagent. 
Results in tubes 1 and 2. 
Time. 
A. 
B. 
C. 
D. 
10 min. 
no change noticeable 
almost pearl blue 
no change 
pearl blue 
30 min. 
almost pearl blue 
deeper than pearl 
blue 
ditto 
pale Windsor blue 
1 hour 
deeper than pearl 
blue 
pale Windsor blue 
ditto 
almost light Windsor 
blue 
2 hrs. 
deeper than pale 
Windsor blue 
almost light Wind- 
sor blue 
ditto 
ditto 
3 hrs. 
light Windsor blue 
ditto 
very slight tinge of 
blue 
ditto 
ditto 
5 hrs. 
ditto 
ditto 
ditto 
10 hrs. 
lighter than pale 
Windsor blue 
lighter than pale 
Windsor blue 
ditto 
pearl blue 
24 hrs. 
lighter than pearl 
blue 
lighter than pearl 
blue 
colour a little more 
distinct but still 
very faint 
ditto 
48 hrs. 
almost decolorized 
almost decolorized 
very faint tint 
almost decolorized 
Tube No. 3 in each case remained unchanged throughout the experi- 
ment. 
(b) 2 per cent. Pyrogallic Acid as Reagent. 
Results in tubes 4 and 5. 
Time. 
A. 
B. 
C. 
D . 
10 min. 
no change 
no change 
no change 
very slightly yellower 
ffion fnhp n 
30 min. 
very slightly yel- 
distinctly yellower 
not distinguishable 
Lllctli IUUC VJ 
distinctly yellower but 
lower than tube 6 
than tube 6 
from tube 6 
still very pale 
1 hour 
very pale yellow 
pale yellow 
ditto 
colour more distinct 
2 hrs. 
pale yellow 
colour more distinct 
ditto 
ditto 
3 hrs. 
ditto 
bright yellow 
ditto 
bright yellow 
5 hrs. 
bright yellow 
ditto 
ditto 
ditto 
10 hrs. 
ditto 
ditto 
ditto 
ditto 
24 hrs. 
deep brownish yel- 
low 
very deep brownish 
yellow 
ditto 
very deep brownish 
yellow 
48 hrs. 
ditto 
ditto 
ditto 
ditto 
