by Green Plants from certain Organic Compounds. 155 



DlAGBAM NO. 2. 



Stem of Plant 

 Imdw, -rubber tube- 

 Glass lube 



Stem of Plant 

 SodbouLimt, 



Asbestos 



SodctsLvrne 



Asbestos 



shown in diagram, by a glass tube — fitting into the cork — having a 

 piece of india-rubber tubing slipped over its end and a portion of 

 the stem, fastened with fine copper binding wire in each case. Com- 

 munication between the air in cylinder and that of bell-jar is 

 provided by means of the side tubes, although these prevent the exit 

 of any C0 2 from the cylinder. 



Method for Experiments with Anacharis alsinastrum and Water 



Plants* 



Pieces of the plant, about 8 — 15 cms. long, were placed in distilled 

 water which had been deprived of any dissolved C0 2 by the addition 



* In experiments with cut branches of plants I consider that the conditions ai*e 

 more neai'ly normal with water than land plants, but owing to the difficulty of 

 keeping a supply of water plants under the requisite conditions, I have not made 

 any very extensive use of them in these experiments. 



