257 



When i^unctured by a [)in-[)rick the hqiiid inside the grain oozed out 

 and no further accunndation of it occurred. This showed that it prob- 

 ably was due to the high osmotic pressure inside the intact membranes 

 and to an abundance of available water in the surrounding soil. No 

 swollen grains appeared in cultures in which the moisture content of 

 the soil was but 30% of saturation or less. 



One of the most noticeable injuries, though by no means the most 

 frequent, was a curled and twisted condition of the leaves due to their 

 inability to unfold normally in the process of growth. An examination 

 of the tips of these leaves showed, in the majority of cases, that they 

 were dead and that they adhered to each other on that account. It 

 was possible to produce typical cases of the injury on control seedlings 

 by touching the tip of the growing shoot immediately after it appeared 

 through the coleoptile with an injurious reagent. Of the reagents 

 used for this purpose sulphuric acid was the most certain to cause the 

 abnormal growth. Kerosene applied in the same manner produced the 

 injury, but it was by no means as efifective as the sulphuric acid. The 

 injury appeared occasionally among control seedlings, but there can 

 be no doubt that the unusual frequency of the deformity in treated 

 grains was due to the effects of the kerosene. 



Another abnormality attributable to the kerosene was a much 

 enlarged and thickened coleoptile which the growing plumule occa- 

 sionally failed to rupture. Whenever this unusual development ap- 

 peared it was observed that the plumule had not grown nearly as far in 

 the coleoptile as it ordinarily does. In some instances the plumule failed 

 to develop, leaving the coleoptile entirely empty. This seemed to in- 

 dicate that the coleoptile is less sensitive to the kerosene than the en- 

 closed structures are, and that the enlargement is correlated with the 

 failure of the plumule to develop. 



The most frequent injury was the death of the shoot. This oc- 

 curred many times in grains from which the root grew normally. 

 \^erv rarely in these experiments did the shoot grow^ w^hen the root 

 had been killed. 



The injuries mentioned above were not as distinct from each 

 other as the descriptions might seem to indicate. As a matter of fact 

 there was an imperceptible gradation from one to another. The de- 

 formed leaves seem to represent the first visible injurious effects of the 

 kerosene treatment. Increasing ill effects, due to an increase in the 

 period of immersion, could be followed through a gradually decreasing 

 vitality, to death. The action of the kerosene in producing injuries, 

 and other evidences to be presented later, indicate that kerosene is not 

 a violent poison to the growing corn-seedling. 



