385 
or germ tube from the particle of copper compound nearest to it ; 
while the fungicidal action of the particle only took place when this 
distance was very small. Another point determined was that there 
was no secretion from spores, provided with a special, thick protec- 
tive wall, and that these could only be killed after the formation of 
a germ tube. This makes it still more improbable that the epidermal 
cells of the sprayed leaves can give rise to the necessary secretion, 
as these also are furnished with a special thick cuticle in almost all 
cases. 
These results have an important practical bearing on the applica- 
tion of Bordeaux mixture. In the first place, they indicate that the 
mixture is of more service as a preventive than as a remedy ; this is 
supported by actual results. In cases where fungi have already 
gained a hold on the leaves before spraying, the hyphae in the plant 
tissues will not come into intimate contact with the particles of copper 
compound on the sprayed surfaces, and will, therefore, not be affected. 
In the second place, the film of copper compounds deposited 
must be even and universal, for, if small untreated areas are left, 
fungus spores will be able to germinate on them unharmed, and the 
resulting hyphae will penetrate the internal tissues underlying the 
fungicidal film, without coming into close contact with this, and, 
therefore, without receiving any check. It is because of the advan- 
tage gaind by uniformity in the film deposited that a second spraying 
is particularly beneficial. Excess of lime in the mixture would appear 
to have but little effect on its action, except in so far as it increases 
the distances between individual particles of the copper compounds 
in the film. 
A final point not considered by these workers is of importance in 
the tropics. Frequently, extra adhesives must be added to Bordeaux 
mixture when it is used in places where the rainfall is high. The 
choice of such adhesives requires care, since they might conceivably 
form a film over the particles of copper compounds, such as would 
prevent the secretions of the fungi from exerting their solvent action 
on those particles. 
(West Indian Agricultural News VoL X, No. 245., 
BROWN’S SPECIFIC 
FOR 
DYSENTERY 
AND 
DIARRHOEA. 
To -be had at the Singapore Dispensary and of Miss Brown, 
Grassdale, River Valley Road, Singapore :: :: :: :: 
