182 DISEASES OF GLASSHOUSE PLANTS 
later, the best known compound is “ liver of sulphur,” 
or potassium sulphide. This is dissolved in water at 
the rate of 3 to 10 ounces per 10 gallons of water for 
spraying purposes, but it is important to obtain a guaran- 
teed pure sample, as some samples have been found to 
be highly caustic and cause injury to delicate foliage. | 
For general purposes a solution of 4 ounce to 1 gallon of 
water will be found most suitable. The solution should 
be used immediately it is prepared as it loses value upon 
standing. 
Lime sulphur prepared from freshly burnt stone lime, 
flowers of sulphur, and water has valuable fungicidal 
properties. The finished product is a deep amber- 
coloured liquid, and while it can be made at home its 
preparation requires a considerable amount of skill, and 
it is advisable to procure the ready-made article from a 
reliable commercial firm. ‘The manufactured article is 
sold at different concentrations, which are indicated by 
the specific gravities marked on the label. Generally 
the specific gravity is 1:3, but it is necessary to know 
this, so that suitable dilutions may be made for spraying 
purposes. The solution deteriorates upon standing and 
should be used immediately. 
Of recent years ammonium polysulphide has come 
into use as a fungicide as the result of investigations by 
Professor Salmon and Dr. Eyre. It has proved extremely 
valuable in controlling many diseases, and will probably 
have a wide application in the future. Concentrated 
ammonium polysulphide is of a dark red colour in bulk, 
becoming yellow in dilution. It is extremely pungent 
and smells strongly of ammonia. It should be stored in 
a cool place in tightly stoppered vessels, and the vapours 
should not be inhaled, as they are harmful. The diluted 
solution, however, is harmless. The compound can be 
obtained in two concentrations, namely, ‘“‘ A.P.S. 1918” 
and “‘ A.P.S, 1919,” the latter being approximately twice 
as strong as the former. 
For spray purposes 1 gallon of “ A.P.S. 1918” or 
