250 Bulletin 144. 



igan Farmer of Feb. 13, 1897, Dr. R. C. Kedzie, of the Michigan 

 Agricultural College, gives the following method of preparing it, which 

 may well be termed the " Kedzie mixture." " Dissolve the arsenic by 

 boiling with carbonate of soda, and thus insure complete solution ; 

 which solution can be kept ready to make a spraying solution when 

 wanted." Then more specific directions follow, which are, '' To make 

 material for 800 gallons of spraying mixture, boil two pounds of while 

 arsenic with eight pounds of salsoda (crystals of carbonate of soda, 

 • washing soda,' found in every grocery and drug shop) in two gallons 

 of water. Boil these materials in any iron pot not used for other 

 purposes. Boil for fifteen minutes, or till the arsenic dissolves, leaving 

 only a small, muddy sediment. Put this solution into a two- gallon 

 jug and label ' Poison — stock material for spraying mixture.' " 



" The spraying mixture can be prepared whenever required, and in 

 the quantity needed at the time, by slaking two pounds of lime, add- 

 ing this to forty gallons of water; pour into this a pint of the stock 

 arsenic solution. Mix by stirring thoroughly, and the spraying mixture 

 is ready for use. The arsenic in this mixture is equivalent to four 

 ounces of Paris green." 



In other words, the stock solution may be made by boiling together 

 white arsenic and salsoda, at the rate of one pound of the former to four 

 of the latter. This will keep indefinitely in a closed vessel, and as it 

 is extremely poisonous it should be carefully taken care of. In apply- 

 ing this stock solution, use two pounds of fresh lime for every pint of 

 the solution. One pint is sufficient to put into a barrel of water. 



The materials for this poison cost about 31^ cents a barrel, making 

 a very cheap and effective poison. 



We do not know that this substitute for Paris green has been tried 

 with Bordeaux mixture, but in answer to a question on this point. Dr. 

 Kedzie replied that he saw no objection to the two mixtures being 

 used together. 



Our observations upon the effectiveness of this mixture have been 

 confined to its action on potato bugs and here it has proved a very 

 satisfactory substitute for Paris green. It has several advantages over 

 Paris green, chief of which are its cheapness and uniformity of 

 strength. 



Since the arsenic, in the form in which it exists in the stock solu- 

 tion, is extremely caustic on the foliage, the addition of a sufficient 



