260 



the "seed" of Hordeum vulgarc to be enclosed in a semi-permeable 

 membrane. He found the aleurone layer of Hordeum vulgar e to con- 

 tain a pigment which serves as an indicator for acids and alkalis. This 

 was not only a very interesting discovery but one which materially 

 aided in the successful conduct of his work. He learned that the in- 

 tact membranes of H. vidgare are impermeable to sulphuric acid ; con- 

 sequently when, in the presence of this acid, the purple pigment 

 changed to a pink color it indicated imperfect membranes. Thus it 

 was possible for him to select "seed" with intact membranes for ex- 

 perimental purposes. From all indications, Sudan HI is just as ef- 

 ficient for determining imperfections in the membranes of Zea as are 

 the color reactions described by Brown. 



Schroder ('ii), using Brown's methods, found the same kind 

 of semi-permeable membranes in wheat. More recently Shull ('13), 

 has made similar studies on the tests of Xantliimn glabratiun and 

 demonstrated selective semi-permeability like that found in Hordeum. 



5. MUTILATED MEMBEANES 



To determine the toxic action of kerosene on the embryo, the 

 outer membranes were punctured at several places and also removed. 

 The following tables (Series B, tables 5 to 10 inclusive) give the re- 

 sults. 



Series B 



Tables 5 to 10 inelusive. Effects of kerosene on grains zvith mem- 

 branes punctured before immersion. Champion IVJiite Pearl Corn 

 germinated in a 2f,% saturated soil. 



Table 5. Normal Grains (Control) 



Table 6. Pedicle Eemoved 



