DISEASES AND OTHER ENEMIES, 307 
lons of water. Slake four pounds of lime in five gallons 
of water. When cool, strain the line water into the 
copper solution and add thirty gallons of water, making 
forty-five gallons of the mixture. Ii desirable to poison 
insects at the same time, four ounces of Paris green or 
London purple may be added to this amount of the mix. 
ture. The ammoniacal copper carbonate solution, alsa 
diluted to half the original strength, is made by adding 
to five ounces of copper carbonate enough water to make 
a thick paste. On this pour three pints of strong aqua 
ammonia, or enough to dissolve the paste. Add forty- 
five gallons of water. Paris green should not be used 
with this. To make the potassium sulphide solution, 
dissolve one ounce of potassium sulphide in two gallons 
of water. For larger quantities of any of the solutions 
use the same proportions. The treatment of insects by 
pyrethrum or insect powder, and by arsenites, and the 
remedies for other pests, are given throughout this vol- 
ume, in the descriptions of the plants they attack. 
For the remedial treatment of tubers and bulbs 
affected with injurious fungi, the successful researches 
on the Potato-scab fungus, by Prof. H. L. Bolley, of 
the North Dakota Experiment Station, are very sugges- 
tive. He succeeded in killing the fungus spores and 
raised a crop of healthy tubers, by treating the washed 
seed tubers to a ninety minutes’ immersion in a weak 
solution, one part in one thousandth, of corrosive subli- 
mate or mercuric bichloride. ‘Two ounces of this deadly 
poison, finely pulverized by the pharmacist, were dis- 
solved in two gallons of hot water for twelve hours, in a 
vessel not made of metal, and then diluted with thirteen 
more gallons of cold water. The cleaned and washed 
tubers were then soaked in this solution for one hour 
and a half. Caution should be used, as the solution is 
poiscnous. The best preventive of all plant diseases is a 
vigorous growth, brought about by healthful conditions 
of fertility, moisture and sunlight. 
