14 



Desniodiwn gyrans. The effects of various drugs are also very- 

 similar. The first result of the application of an anaesthetic like 

 ether is to evoke a transient exaltation, followed by depression 

 and arrest. Poisonous gases also induce a continuous depression 

 of activity. A strong poisonous solution, again, induces a rapid 

 arrest of pulsation. 



It has thus been shown that by the waxing and waning of re- 

 sponse, the variations in the plant's physiological activity, under 

 changing external conditions, may be gauged. It has been 

 shown also how numerous and varied are the factors that go to 

 make up the complexity of plant-responses. It has been shown 

 that stimulus may be modified in its effect, according as it is 

 direct or indirect, and feeble, moderate, or strong. The modify- 

 ing influence of the tonic condition of the tissue has also been 

 shown, according as this is normal, sub-tonic, or fatigued. In 

 the numberless permutations and combinations of these varied 

 factors lies the infinite complexity of the responsive phenomena 

 of Hfe. 



After a discussion of Professor Bose's paper by Doctors 

 Rusby, Richards, and Pond, the meeting of the Club was ad- 

 journed to the second Tuesday in January. 



Marshall A. Howe, 



Secretary p7'o tent. 



OF INTEREST TO TEACHERS 



Food for Thought 



School Science and Mathematics for January gives the following 

 " simple plant experiment " by E. S. Gould, of Galva, Ilhnois. 



" The following device for showing the necessity of COgin photo- 

 synthesis may be of use to teachers of botany, especially where 

 apparatus is limited. 



"A bell glass with a rubber stopper is placed on an ordinary 

 pump plate. The tube C oi the plate is closed with a cork. In 

 the cylinder inside is placed NaOH or Ca(0H)2 to absorb the 

 COj. Air is forced through tube A (tube B being open) for a 

 few minutes until the most of the air in the bell glass is devoid 

 of COj. What CO2 is left in the glass will be absorbed by the 

 NaOH in the cylinder. The air is changed every day so that if 



