156 Mr. E. H. Acton. The Assimilation of Carbon 



of barium acetate solution, sufficient excess of the latter being present 

 to withdraw from the water any C0 2 obtained from respiration. The 

 jars containing water and plants were exposed in a window — 

 receiving some direct sunlight — for two days, at the end of which 

 period leaves tested as described were found to contain no traces of 

 starch. 



The plants were then rapidly transferred to other jars containing the 

 same solutions as used in the previous experiments (see next page), 

 with the addition of sufficient barium acetate to leave an excess of the 

 salt for withdrawal of any C0 2 formed during the experiment, but in 

 no case did the amount of soluble barium salts at the beginning of 

 the experiment exceed 25 per cent, barium (4 - 2 per cent. BaS0 4 on 

 precipitation). The jars in this and the previous experiment were 

 closed by tightly fitting india-rubber corks perforated with two holes 

 through which are inserted glass tubes connected with soda-lime 

 |J -tubes, to allow a free circulation of air in the space above the 

 water, but to deprive any air so entering the apparatus of all traces 

 of C0 2 (diagram No. 3). 



DlAGEAM J^O. 3. 



Soda, Lvrne 



Wetter etc. etc. 

 amtcuurbvrwj 

 por-tums of me> 

 plants cvrwb 

 BarmTrUicetcdc 

 ■to remove CO. 



Sodco Lumt 



w in MMM mum 



