21 R 



ixsKcTiriDKS, funCtICIdes, axd weed killees. 



The <Trexter th'? number of deep wou'ids sustained by the grain in 

 threshing the m )re sensit ve it is. When the grain is wounded noth- 

 ing prevents the penetration of the copper solutions into the interior of 

 ttie grain, and the embryo may be killed by a short immersion in a 

 bath of blue vitriol. Ivins and Welter have made categoric experi- 

 ments in this direction with grain wounded for the purpose. 



TABLE XXIX. — Showing Effect on Germination nf Steeping Injured Grain in 

 Water and in Solutions of Blue Vitriol. 



The unwounded test samples were not injured by steeping from one to 

 two hours in a 0*5 per cent blue vitriol solution, and even a 1 per cent 

 solution when the action of the blae vitriol was stopped by a bath of 

 milk of lime. Now it is a well-known fact that the threshing of grain 

 in the threshing-mill damages about 30 per cent, whereas hand 

 threshing [with the flail] does much less damage. This 30 per cent is 

 generally killed by steeping in a solution of blue vitriol, so that it is 

 necessary to use, in general, 30 per cent more seed to sow the fields 

 when such corn-seed, disinfected by blue vitriol, is used. After a pro- 

 found examination of the subject the greatest authorities, Deherain, 

 Grandeau, Vilmorin, Sorauer, Loverdo, Brefeld, and others, agree on 

 the superiority of the blue vitriol method, used rationally, over other 

 methods of disinfection; it alone possesses the property of still actmg 

 after the sowing of the seed-corn within a certain radius of the latter. 

 It protects them during the period the plant is vulnerable from the 

 germs found in the soil, or which have been brought on to the land 

 with the dung. From that point of view blue vitriol is superior to hot 

 water, sodium sulphide, sodium sulphate, the disinfectant property of 

 which is, however, analogous and the efficiency incontestable. How- 

 ever, blue vitriol, so as not to injure grain, must be used, in a rational 

 manner ; the steeping should be as short as possible, and its action 

 stopped at the right moment by converting it into an inert and insol- 

 uble derivative as soon as it has played its role of disinfectant. The 

 methods recommended by Benedikt Prevost, in 1807, were not much 

 altered by a deeper examination of the subject by Mathieu de Dom- 

 basle. By describing a practical method of disinfection the latter, 

 however, largely helped to make this process general. 



Here is his process : Dissolve 1 lb. of blue vitriol in hot water and 

 make up the bulk to 20 gallons. Immerse the corn-seed into this bath 

 in such a way that a layer of liquor, 4 inches in dej^th, remains above 

 the seed. Stir several times and remove all the floating grains. After 



