\0Q 



TOMATO. 



cyanide when foui- grammes to the four and a half pounds of soil were 

 used. In these pots only the smallest trace of Eelworm could be 

 found, whereas the pots in which the other chemicals were used were 

 a mass of knotted roots. 



"I then tried a second batch, using eight and twelve grammes to 

 the pot, of all the chemicals I had tried previously, except gas-lime, 

 caustic lime, and potassium ferrocyanide, which I abandoned ; and 

 carbolic acid and potassium cyanide, which I tried from six grammes 

 upwards. I now found quite a number of the chemicals seemed to kill 

 the Eelworm. Also that five per cent, of powdered charcoal seemed 

 to kill it. 



" My third batch of experiments were tried in beds of soil in which 

 Cucumbers had been growing (and failed) through the roots being 

 covered with the root-knots. The beds were divided into pieces con- 

 taining fifteen cubic feet of soil, the weight of which would be about 

 twelve cwt. Some of the chemicals previously used were now aban- 

 doned on account of their cost ; and Paris-green and bichloride of 

 mercury were tried for the first time. Up to one and a half cubic feet 

 of powdered charcoal was used, and found of no use whatever; plants 

 grew well. Up to eighty-two ounces of sulphate of iron did not affect 

 worm or plants. Up to twenty- seven ounces of sulphate of copper did 

 not affect either plant or worm. Up to sixty-six ounces of sulphate of 

 potash did not affect either plant or worm. Two ounces of Paris-green 

 made plants sickly, but five and a half ounces did not kill Eelworm. 

 Three ounces of bichloride of mercury injured the plant, but six ounces 

 did not kill Eelworm. Up to sixty-six ounces of sulphate of potash 

 did not affect either plant or Eelworm ; neither did sulphate of 

 magnesia. Sixty-six ounces of sodium hyposulphite checked Eelworm 

 only. But witli thirty-three ounces of carbolic acid, hardly a trace of 

 Eelworm could be found. The little that was found had probably 

 come from the other soil after the effects of the carbolic acid had 

 passed away. I cannot say that the plants were not affected by this 

 quantity, but it was not much, and perhaps not at all. The plants 

 might get a little check from other causes. 



" You will now notice that my second and third batch of experi- 

 ments do not agree with each other. Many things that appeared to 

 kill in the second batch, quite failed in the third. I can only account 

 for it in this way : the second batch were grown in pots on a stage in 

 a greenhouse during June, July, and August. The sun was fearfully 

 hot, and I had to complain to my man who had charge of the watenng 

 these plants for allowing them frequently to get very dry ; and I think 

 it probable that the continual watering and drying, with the hot sun 

 shining on and almost baking the pots, acted injuriously on the 

 Eelworm. 



