142 



Mr. F. Kidd. 



taken from the parent plant were used as material, in the other dried peas, 

 set in germinating conditions save for the absence of oxygen. In both these 

 cases it is seen that the anaerobic C0 2 production has been reduced in relation 

 to the amount of carbon dioxide present in the atmospheres. Quite similar 

 results were also obtained with white mustard seeds. 



In the foregoing experiments, the first fact which stands clearly out is 

 that the anaerobic output of CO2 varies in some inverse relation to the 

 amount of CO2 present in an atmosphere. It would clearly be possible to 

 attribute these graded productions of CO2 to different degrees of dis- 

 organisation of the CO2 producing mechanism. If any such permanent 

 disorganisation is produced its effect should become visible in lowered 

 respiration when the seeds are removed from the excess of CO2 back to pure 

 nitrogen. This question was tested experimentally. Estimations of C0 2 

 production were continued after the material had been returned to nitrogen 

 or air free from CO2. It was found as the result that the CO2 production, in 

 any parallel series of experiments, returned to an equality in all cases with 

 that of the control in which no C0 2 had been present from the beginning 

 (Tables IV and Y). 



Table IV. — Showing that Normal Respiratory Activity is Resumed after 

 Removal of Retarding Concentrations of Carbon Dioxide. 





Anaerobic C0 2 production. 





















After removal 



Initial 





In the presence o 



E C0 2 concentrations. 





of C0 2 con- 



COo in 



















centrations. 























N 2 and 





















co 2 . 





Estimated from increased pressure after 





Checked 



by 



Estimated by 



















analyses 



analyses after 



















after 



further 47 hrs. 





19 hrs. 



24hrs. 



31 hrs. 



44 lirs. 



51 hrs. 



67 hrs. 



90 hrs. 



90 hrs. 





per cent. 



c.c. 



c.c. 



c.c. 



c.c. 



c.c. 



c.c. 



c.c. 



c.c. 



c.c. 







27 



33 



39 



47 



60 



66 . 



83 



89 



41 



10 



21 



25 



30 



37 



43 



52 



69 



74 



44 



20 



19 



21 



26 



32 



42 



45 



60 



62 



43 



40 



14 



16 



20 



24 



33 



35 



48 



46 



43 



80 



9 



10 



13 



16 



24 



26 



39 



34 



50 



Conducted in dim diffuse light. In each experiment 25 Early Sunrise peas, dry weight 8 grm. 

 set dry in 12 c.c. boiled distilled H 2 0, being just sufficient to allow them to fully swell. Peas 

 and flasks sterilised with bromine. Two hours allowed before first reading. Temperature 20° 

 first 20 hours, after that laboratory temperature 16-18° C. 



