356 BOTANICAL GAZETTE [MAY 
Experiment IV .—Effect of bromine absorption on the toxicity of paper 
smoke 
In this experiment the washed smoke from the loosely rolled 
paper cigarette was absorbed with bromine by the gas analysis 
method described by Hempet. All traces of bromine were later 
absorbed by washing with 40 per cent NaOH. As is well known, 
bromine absorbs the heavy hydrocarbons (acetylene, ethylene, 
etc., with their higher homologues). It does not absorb methane 
or carbon monoxide. If the substance determining the toxicity of 
this smoke is one of the heavy hydrocarbons, this treatment should 
reduce the toxicity. If it is carbon monoxide 
or methane, it should not greatly modify the 
toxicity. The cultures were sealed in 1o-liter 
Fic. 3.—Responses to paper smoke: a, check; }, response to 20 cc. of smoke from 
tightly rolled paper cigarette in 10-liter chamber; c, response to 50 cc. of smoke. 
chambers and subjected to the various sorts and concentrations of 
smoke for three days. The data show the condition of the epi- 
cotyls at the close of the experiment. 
1. Check; epicotyls 5-11 cm. tall, vertical and slim. 
2. 20 cc. washed smoke not absorbed with bromine; epicotyls 3-4. 5 cm. 
long; swollen portion 1—1.5 cm. long, with declination of 75°-90° 
3. 25 cc. (duplicates) washed smoke absorbed with bromine; epicotyls 
6-12 cm. tall, vertical and slim. 
4. 85 cc. washed smoke absorbed with bromine; epicotyls 4-9 cm. tall, 
vertical and slim. 
5. 69 cc. washed smoke absorbed with bromine; epicotyls 4-9 cm. tall, 
slim and straight. 
