41 



of the experiments made along these lines. The name of each solu- 

 tion tried is given in the first column, and the strength of the solu- 

 tion, the amount applied, and the size and number of pots are also 

 given. 



The strengths of the solutions are given in proportion as in the 

 previous table, for example, 1-200, which indicates that one part 

 of the solution was used to 200 parts of water or practically a 0.5% 

 solution. 



While the experiments with chemicals given in this table constitute 

 only a few of the many which we have made, they are nevertheless 

 representative as far as reaching any positive results are concerned. 

 In fact the solutions given in the table are those which in our labora- 

 atory experiments appeared to give the most promising results and as 

 we have already pointed out some of them have been recommended by 

 other experimenters. From the many hundreds of microscopic exami- 

 nations of the young cucumber roots and previously infested soil in 

 which they were growing there can be no doubt but that some of 

 these solutions when applied quite strong and in considerable quan- 

 tities are capable of killing many of the adult worms in the soil. 

 We have repeatedly found many dead nematodes in the soil after 

 applying large amounts of Potassium permanganate of the strength of 

 1-200 or 1-300, or of Potassium sulfid at the rate of 1-250, etc., and all 

 of the experiments with Carbon bisulfid, commercial Ammonia, and 

 most of those with Ammonia water from gas works showed the same 

 thing. The remaining solutions appeared to have no effect upon 

 the adult worms at the strengths at which we used them and even 

 where we covered the surface of the soil with lime to a depth of 1 inch 

 and watered the same with a saturated solution every few days, nem- 

 atodes were abundant in the soil. Evidently the most effective 

 solutions for the worms were Carbon bisulfid and the two Ammonia 

 solutions. The killing of a few adult worms in the soil, however, is 

 of absolutely no consequence. As long as the nematode eggs are 

 present a new crop of large proportions can be expected within a 

 few days. The solutions appear to have no effect upon the eggs 

 because they are protected by an almost impervious coating. Dr. 

 N. A. Cobb states that the young embryo is well protected in the 

 shell and can withstand very strong poisons. 



