344 



Plant Physiology 



control. Plan both sets under conditions favorable for growth, 

 and compare the time periods required for development. It 

 should be remembered that positive results are obtained by such 



II 



-" 



FIG. 91. A convenient etherization chamber, sectional view, showing 

 also carrier (c), groove for melted paraffin (#), and method of intro- 

 ducing ether. 



forcing only when the plants treated are not in condition normally 

 to show immediate growth. Potted plants may be inverted and 

 immersed to the edge of the pot. 



Etherization. - - In a tight zinc box such as shown in Fig. 91, 



