216 Prof. Bose and Mr. Das. Physiological Investigations with 



lower end of the cut stem is mounted on a T-tube, with funnel-attachment 

 and exit-tube, as shown in fig. 1. The other two cut ends — of the stem and 

 of the petiole — may be covered with moist cloth or may be closed with 

 collodion flexile to prevent rapid evaporation and drying up of the specimen. 

 A slight hydrostatic pressure maintains the specimen in a moderately turgid 



Fig. 1. — The Kesonant Eecorder, with petiole-pulvinus preparation. (From a 



photograph.) 



condition. A preparation thus made is insensitive at the beginning, but 

 if left undisturbed it slowly recovers its excitability. The history of the 

 depression of excitability after shock of preparation and its gradual restora- 

 tion is graphically illustrated by a series of records made by the plant (tig. 3). 



The petiole-pulvinus preparation thus made offers all facilities for experi- 

 ment. Owing to its small size it can be easily manipulated ; it can be 



