268 



and carried through the vascular tissues to the leaves, where it was 

 stored in quantities sufficiently large to make its presence easily deter- 

 minable. Unfortunately Kryz continued the treatment until the plants 

 were killed. He seems not to have paid any attention to the power 

 of recovery of the plant from injuries not at once fatal. 



These investigations led me to believe that under favorable con- 

 ditions a limited amount of kerosene might be absorbed and disposed 

 of, without injury, by the growing corn seedling. Observations con- 

 firmed this belief. The coleoptiles of seedlings grown from grains 

 immersed in colored oil frequently showed the red stain. In soils of 

 low moisture content these seedlings developed normally, while in soils 

 of high moisture content they were either killed or showed pronounced 

 injury. Numerous attempts were made to demonstrate the presence 

 of the oil in the tissues. Sections were treated with Sudan IlT, 

 alkannin, and picric acid benzol (5), but because of the large amount 

 of oil normally present in the structures of the young corn seedling 

 and the very small amount of kerosene which ordinarily is present, 

 the results were not successful. No satisfactory test for demonstrat- 

 ing the presence of kerosene in very small quantities has been found. 



The "experiments of Kryz w^ere repeated in a modified form and 

 his results confirmed. Corn seedlings were grown on filter-paper so 

 that the roots penetrated the paper and entered soil contained in a pot 

 below. When the seedlings were about three inches tall, from i to 3 

 drops of Sudan III kerosene were applied to the old grains at the base 

 of the seedlings. A drop was equal to one-fiftieth cubic centimeter. 

 In a few^ minutes the stain showed prominently in the stems of the 

 seedlings and eventuallv reached the leaves in quantities sufficiently 

 large to be plainly visible to the naked eye. All the seedlings treated 

 with three drops died within five days after the treatment. The 

 majority of the seedlings treated with one and two drops recovered. 

 The amount of oil disposed of was certainly many times as much as 

 could be retained in the dry grains immersed in oil and afterwards 

 treated to eliminate it. It is apparent that the older seedlings can dis- 

 pose of a much greater amount of oil than the younger ones. 



It is evident that within certain limits the seedlings are not in- 

 jured by the oil present at the time of planting provided growth is 

 initiated in the presence of a minimum amount of water. The small 

 quantities of kerosene are toxic in proportion to the increase of the 

 moisture content of the soil. In the 50 and 75% saturated soils the 

 dormant period of the grain is always less than 36 hours, while in a 

 25% saturation the time is extended to approximately five days. This 

 increase of time affords the seedling an opportunity to dispose of the 

 oils much more slowly, and it does so without injurious effects. 



