32 



(sprinkling- and stirring- till thoroughly moistened), Prof. C. A. Zavitz 

 (Bull. 140, pp. 14-15) obtained the following results with oats, the figures 

 giving the percentage of smutted heads in the crop obtained from sowing 

 the treated grain : 



(a) o per cent. 



(b) o " 



Untreated 7.0 . " 



These results show that both treatments with formalin entirely 



destroy the smut spores adhering to seed grain. These formulae will 



also serve for the treatment of wheat. 



Corrosive Sublimate. 



This chemical is made up of mercury and chlorine, one atom 

 of mercury in combination with two atoms of chlorine, repre- 

 sented by chemists as HgCl§. It is medicinal in small doses, 

 but large doses are extremely poisonous ; and its solution in water 

 sprayed onto plants would, for this reason, make a very deadly food for 

 biting insects. As an insecticide, however, it is not much used, on ac- 

 count of its corrosive action, but as a remedy for potato scab it is very 

 valuable when used in the following quantities (handle in a wooden 

 vessel) : 



Corrosive sublimate 1 ounce. 



Water 7 to 8 gallons. 



The solution and treated potatoes are both highly poisonous. 



Liver of Sulphur, Potassium Sulphide. 



This substance is a compound of the elements potassium and sulphur 

 (KjS) and its solution possesses considerable value as a treatment for 

 certain fungous diseases, such as the gooseberry mildew; but it is not 

 nearly so energetic as are the copper compounds. It is used to some 

 extent in treating grains for smut, for which the following quanities are 

 recommended : 



Potassium sulphide 1 pound. 



Water 24 gallons. 



This solution should be used in a wooden vessel, and must be applied 

 soon after making, since on standing in contact with air the sulphide 

 becomes oxidized to the sulphate and thus loses in strength. 



Acknowledgments. 



The reports, bulletins, etc., of the Dominion and Provincial De- 

 partments of Agriculture, as well as those of the United States Depart- 

 ment of Agriculture and the Experiment Stations of the various States 

 of the Union, have been freely used in gathering the data embodied in 

 this bulletin. Where possible, reference has been made to the source of 

 the information, but in all cases the original source of the data could not 

 be obtained. 



