96 



INTERCELLULAR SPACES. 



[CH. IV 



is important. The following answer well: Arwm macu- 

 latum, Ranunculus ficaria, Eranthis hiemalis, Galtha 

 palustris, Primula sinensis, Limnanthemum sp. 



The leaf stalk is fixed air-tight in a rubber cork which 

 fits a bottle filled with water. The leaf can be fixed by 

 piercing the cork with a hole too small for the stalk, and 

 dividing the cork longitudinally down one side till the 

 hole is laid open. Or an undivided hole may be used 

 if made air tight with wax mixture. Through a second 

 hole in the cork passes a glass tube (it must not dip into 

 the water) connected with the air-pump. When the pump 

 is set in action a stream of bubbles emerges from the cut 

 end of the stalk which is below the surface of the water. 

 The reverse experiment may also be made by placing the 

 lamina in the water and the cut end in the air. 



(120) Injection with water. 



Many leaves e.g. Ficaria, Limnan- 

 themum, Hydrocharis can be injected 

 by sucking the stalk with the mouth 

 while the lamina is in water. Or the 

 air pump may be applied. It is easy 

 to ascertain the pressure necessary for 

 injection by the following arrange- 

 ment. 



The leaf is attached to one arm of 

 a T tube : by means of the second arm 

 suction is applied, and the third ends 

 in a bent tube dipping into mercury. 

 If the junction between the stalk and 



Fio. 19. Exp. 120. 



