322 
Garden Work 
the nature of the disease. The spores are so very minute 
that they float about in the atmosphere, the slightest wind 
carrying them far from where they are produced, and 
wherever they alight on a Potato leaf, on which is the 
slightest moisture, they will germinate, and so spread the 
disease. The disease is most prevalent in damp situations. 
In light, dry seasons one is not so much troubled with it, 
as sunshine itself is a check, and, the leaves being dry, the 
spores which may be formed do not have a chance of 
dividing into the small zoospores, and these again have 
no opportunity of germinating. In the present state of 
horticulture and agriculture, however, whilst no law exists 
compelling people to take care of their crops, and keep 
them free from disease, precautions must be taken to pre- 
vent the swarms of spores flying from a neighbour’s garden 
or field from alighting on the leaves of our Potatoes, 
and causing the disease. This is done by spraying with 
Bordeaux mixture. This is the best preventive known 
at present. Not only does it arrest the spread of the 
disease, but it stimulates the growth of the plants, and 
increases their yield. 
It is made up of — 
12 lb. copper sulphate (bluestone). 
8 „ quicklime, 
ioo gall, water. 
Or — 
io oz. copper sulphate. 
6 „ quicklime. 
5 gall, water. 
The copper sulphate should be dissolved by putting 
it into a small quantity of boiling water. This should then 
