266 



After twenty days' immersion in Sudan III kerosene, and after 

 germination tests had proven all the grains dead, the remaining grains 

 of the new corn were carefully examined to determine the number 

 showing penetration of the stain. Of the i6i grains, 24, or approxi- 

 mately 15%, were stained. Twenty-four days later — 74 days' immer- 

 sion — the number had increased to 45, or 25%. If one should attempt 

 to judge the viability of the grains by the presence or absence of the 

 stain, as was done so effectively in the dry grains, the rate of germina- 

 tion should be approximately 75%. Both stained and unstained 

 grains, however, had lost all power of germination and the presence 

 of kerosene was easily demonstrated in both. The conclusion nat- 

 urally follows that the membranes of the moist grains permit the 

 penetration of the kerosene, but that they effectively prevent the pas- 

 sage of the Sudan III. The percentage of grains stained by Sudan III 

 was approximately the same as in the dry grains. This supports the 

 view previously expressed; namely, that the stained embryo is an in- 

 dication of imperfect membranes. 



7. VARIATIONS IN SOIL MOISTURE 



That some grains of corn bear immersion for a period of eight 

 years in kerosene is experimentally proven. This, however, is not true 

 of all grains of like origin subjected to similar treatment. In every 

 sample taken at random a certain percentage of the grains fail to 

 germinate after a comparatively short period of immersion. By means 

 of the Sudan III it has been conclusively established that a limited 

 number of grains of a random sample are stained and that these even- 

 tually fail to germinate even under the most favorable conditions. 

 Death in these instances is due to the toxic action of the kerosene on 

 the dormant embryo. Since it has been shown that the dry mem- 

 branes are impermeable or only slightly permeable to kerosene, the 

 presence of the oil within the membranes, in sufficient quantities to 

 cause death, is attributable to imperfect membranes. The presence of 

 small quantities of kerosene within the grain, however, does not neces- 

 sarily prove injurious. Grains immersed in kerosene for the same 

 periods of time give very unlike results when placed under different 

 conditions for germination. It was found that in the presence of 

 abundant moisture the injurious effects of the kerosene treatment are 

 especially marked. In the experiments (Series A) in which grains, 

 similarly treated with kerosene, were placed in soils with different 

 moisture content, this injury was clearly brought out. When the 

 amount of water in the soil was reduced from 30% saturation (Series 

 A, Table i) to 25% saturation (Series B, Table 5) the per cent, of 



