the Effect of Formaldehyde on Living Plants. 
425 
Effect of Acetaldehyde in the Air , in Light. 
Experiment I. December, 19 12. 
Source of aldehyde : pure liquid aldehyde. 
Temperature range, 8° to 14 0 . 
Duration , 14 days . 
Atmosphere. Orig. dry weight. Final dry weight. Final / orig. weight. 
Air - C 0 2 + CH 3 CH 2 0 0*3845 grm. 0*3326 grm. 86*50 % 
Air - C 0 2 0*3850 ,, 0*3111 „ 80*83% 
Air + C 0 2 0*3845 „ 0*3279 „ 85*28 % 
Notes . — The effect of acetaldehyde on the plants, in this concentration, 
was strongly toxic. Most of the seeds germinated, and in some the 
cotyledons were unfolded, but they remained colourless, and the roots 
showed no geotropism. 
The high value merely means inhibition of respiration. 
Experiment II. February to March, 1912. 
Source of aldehyde : 10 % water solution. 
Temperature range, 9*5° to n°. 
Duration , 19 days. 
Atmosphere. Orig. dry weight. Final dry weight. Final J orig. weight. 
Air - CO a + CH s CH 2 0 0*3910 grm. 0*2915 grm. 74*54 % 
Air — C 0 2 0*3885 ,, 0*2545 „ 65*53% 
Air + C 0 2 0*3860 „ 0*3530 ,, 9 I *45 % 
Notes . — The increase in weight shown in presence of acetic aldehyde 
was probably due to retardation of respiration and general growth, as the 
cotyledons were unfolded a day later in aldehyde than in the ‘ control ’ 
cultures. There were no other symptoms of poisoning. The temperature 
and light conditions were so poor that the experiment was not considered 
conclusive. 
Experiment III. July to August, 1912. 
Source of aldehyde : 40 % water solution. 
Temperature range, 17*5° to 23*5°. 
Duration , 28 days. 
Atmosphere. 
Air — C0 2 + CH 2 0 
Air — C0 2 + CH 2 0 
Air — C0 2 
Air — C0 2 
Air + C0 2 
Air + C0 2 
Orig. dry weight. 
0*3870 grm. 
o*3875 » 
0*3865 „ 
0*3860 „ 
0*3845 » 
0-3850 „ 
Final dry weight. 
0*2446 grm. 
0*2615 „ 
0-2455 » 
lost 
o-43 2 5 „ 
o*3775 » 
Final / orig. weight . 
63*20 % 
60*67 % 
63*52 % 
112*40 % 
98*95 % 
Notes . — The experiment was run with two cultures in each bell-jar, the 
first of the two cultures being nearer the light in every case ; unfortunately 
the second culture without C 0 2 was lost by an accident. The experiment 
