POTASSIUM SULPHIDE (LIVER OF SULPHUR). 115 



previously. The powder used in the beginning and known under the 

 name "Ceres," is nothing more than potassium sulphide. The 

 numerous experiments of Bolley, Rostrup, and Selby show, however, 

 that the sulphide is not capable of rendering better services than the 

 Jensen hot- water treatment or that of Kuhn's with blue vitriol or that 

 by mercuric chloride. It generally gives very irregular and some- 

 times imperfect results, for example, against Syinit of Wheat (Eostrup). 

 It has, however, a serious application in the disinfection of oats, where 

 it is superior to any other treatment in destroying the spores of 

 Ustilago Avence, Rost. (loose smut of oats). This treatment is practised 

 in Denmark where it is highly esteemed. Steeping should last twenty- 

 four hours in a 0*75 per cent solution. 



Helminthosporimu gramineuvi, Eriks. (black mould of cereals). — 

 Kolpin Kavn found steeping grain in the sulphide is a good precaution 

 against this disease. 



Spraying with Dilute Solutions. — The Erysiphece, the mycelium 

 of which is not protected by the tissue of the plant attacked, may be 

 combated by potassium polysulphides. Owing to their decomposition 

 the sulphur is deposited between the filaments spread on the surface 

 of the organs attacked, and acts in a more certain manner than sulphur 

 used against the same disease. In spite of their properties the 

 sulphides of potassium are not used to combat the oidium. Gardeners 

 use them against MicrospkcBra Grossularice, Wallr. (gooseberry leaf- 

 mildew) ; Spharotheca Mors Uvce, B. et C. (American gooseberry 

 mildew), which they cure radically. Close prefers a 0"3 per cent solu- 

 tion of potassium sulphide to the fungicides, usually employed by sol, 

 formol, and bouillie bordelaise. Goiif advises spraying with a 0"2 — 0-4 

 per cent solution as soon as the leaves appear, and to renew it after 

 each heavy rain until the plants are completely in leaf, and from time to> 

 time in summer. He obtained the following results : The fruit garden 

 check plots showed 11 S per cent diseased plants, after 0*2 per cent treat- 

 ment 7 per cent, and after 0-4 per cent 1-7 per cent of diseased plants.. 



Sphceroth'ica pannosa, Lev. (rose and peach mildew). — This fungus 

 may be combated efficaciously by potassium sulphide. Vesque recom- 

 mends spraying with 1 per cent solutions, Mohr 2 per cent liver of 

 sulphur, to which he adds 2 per cent of glycerine to render it more 

 active and adherent. A concentrated bouillie is prepared by dissolving 

 200 grammes of liver of sulphur and 200 grammes of glycerine in a 

 litre of water (say 2 lb. of each in a gallon of water) and the solution 

 kept out of contact with air until required for use, when it is diluted 

 with ten times its bulk of water. 



Sjohcerotheca Castagnei (liop mildew). — Salmon recommends Q-l 

 per cent solutions, Selby 0-2 per cent solutions. 



Amongst the fungi living in the interior of plants which cannot be 

 reached, a certain number may be combated by destroying the conidio- 

 spores which contribute to their rapid propagation. These are : — 



Alter naria BrassiccB f. nigrescens, Peglion (scorching of the leaves 

 of the melon). — Sturgis used potassium sulphide with much success. 



Sphcerella Fragaria, Sacc. (spotting of the leaves of the straw- 

 berry). — Potassium sulphide has been used successfully in America by 



