129 



acid, pyridine or quiiiolinc failed to greatly increase 

 the infertility of the infertile soils used. To be sure, the 

 application of such compounds in ratios as great as 

 1000 parts per million of dry soil decreased the yields 

 in some cases, where the crop was planted on the same 

 day that these heavy ap|)lications -were made. But 

 when these compounds had been in the soil for a few 

 months, the evidence shows that little or no toxic ef- 

 fects were to be found. Indeed, tlie nitrogenous com- 

 pounds had a ])eneficial effect in all cases reported, 

 though there was evidence that these may be harmful 

 for a short time after the a|)plications are made. This 

 constitutes good evidence that rapid chemical or bio- 

 chemical transformation of these compounds into 

 beneficial or inert forms occurs in unsterlized soils 

 under the conditions of these experiments. Slight in- 

 jury to oats was apparent in most of the heavy treat- 

 ments of pyridine and quinoline during the first wrecks 

 of growth; but this injurious action disappeared, and 

 the i)ots so treated usually produced crops which com- 

 pared favorably wdth those produced by the nitrate 

 treated pots. 



It is interesting to note that, had these experiments 

 l)een terminated when the plants w^ere only 15 days 

 old, a ([uite different set of conclusions would have 

 been drawn from the work. Both pyridine and quino- 

 line would have been found to be harmful, while it 

 is likely that vanillin and coumarin would have been 

 recorded not injurious. Neither of these latter showed 

 injury to oats during. the first few days of growth; only 

 in the later stages could their effect be noted, and that 

 effect was a simple retardation of growth. It is very 

 evident, then, that plants must be grown for consider- 

 able periods of time, if erroneous conclusions arc to be 

 avoided. 



The increased amount of stooling induced in oats bv 

 pyridine and to a less extent by ([uinoline, is worthy 

 of attention. The pyridine treated pots could be pick- 

 ed very easily after the ])lanls were about 40 days old, 

 due to vigorous stooling produced. Reference to 

 the photographs on Plate II ([uite clearly shows the 

 great number of stems produced on the pyridine 

 treated pots. This increased stooling caused by pyri- 

 dine has been noted both years, and in all of the soils 

 tested. 



