12.') 



applicalion of pyridine in llic cxpcrimcnls concUiclod 

 previous lo lliose here reported. During the two sea- 

 sfHis in wliieli these experiments were in j)rogress, this 

 third pot received a total of 81 grams of compounds 

 which, in sohition cultures, have been shown to be high- 

 ly toxic to [)lants. And duiing the last season, this pot 

 received (VA grams of toxic compounds, all of which 

 wvve applied lo the soil on the same day on which the 

 oats were planted. If the soil used in this work weighed 

 four million pounds to the acre, this 63 grams of toxins 

 is equivalent to about seven thousand pounds 

 per acre, based on the surface six inches. The phos- 

 phate and potash treatment which has been given the 

 oats was repeated for the corn, but none of the special 

 treatments were repeated. 



By the time that the crop was two wrecks old, the 

 phmts in the third pot began to take on a darker green 

 color than those in the other two pots, and soon there- 

 after a vigorous stooling began. When the experiment 

 was terminated, the plants of the third pot had stooled 

 to such an extent that nearly the whole surface of the 

 pot was covered with plant stems. A study of the pho- 

 tographs shown in Plate VIII will give a good idea of 

 the appearance of the three pots just before harvest. 



A crop of corn followed after the oats. As was the 

 case with oats, the corn plants in the third pot made a 

 better growth and had a darker green color than did 

 those in the other two pots. These color and growth 

 differences were noticeable by the time that the corn 

 was a week old, and remained until the harvest of the 

 crop. At no time was there the slightest indication of 

 injury to either of the two crops by the enormously 

 heavy applications of toxic compounds which had been 

 made. Both the photographs and the crop weights give 

 abundance of proof that the results obtained with soil 

 cultures are radically ditTerent from those obtained 

 with solution cultures. The weights of the green crops 

 are presented in Table IX. 



