1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 353 
effective; while on the basis of the dry weight necessary to produce 
the smoke, the paper is more than twice and the cigarette only about 
one-third as effective as the cigar. The toxicity of the several 
smokes undoubtedly depends in part on the oxygen supply during 
the smoking. This will determine to some degree the amount of 
dry distillation gases escaping oxidation, although much of these will 
escape oxidation under any condition, for the heat is sufficient 
beyond the ignited portion of the cigar or cigarette to cause dry 
distillation, and here no burning of the dry distillation gases can 
occur. When the same paper used in making the paper cigarettes 
was burned as an open sheet in the 1o-liter container, it required 
0.14-0.21 gm. to give NELJuBOW’s third response. When burned 
in this way, the paper smoke is approximately 0.02 as toxic for this 
seedling. Burning the open sheet insures a more complete oxida- 
tion of the dry distillation carbon-bearing gases, both because of 
better oxygen supply and because of surer contact with the flame. 
It should be stated that the paper cigarettes used, though rolled 
only to moderate tightness, were difficult to smoke in the machine. 
They required considerable more suction than the cigarette and 
probably had low oxygen supply, as later analyses will indicate. 
Experiment III.—Effect of washed smoke and chemical analyses 
Two paper cigarettes, one loosely rolled and the other tightly, 
were smoked and washed with 15 per cent H,SO, and 4o per cent 
NaOH and stored separately. The analyses of this sort of smoke 
according to the methods described by HEMPEL (14) are as follows: 
Loosely wrapped paper cigarette; 4.78 gm. of paper smoked, with a 
yield of 8384 cc. of washed smoke. 
A B 
Volume of smoke taken for analysis..........-: 99.6 ce 99.9 cc. 
Volume after absorption with 4o per cent NaOH. 6 99-9 
Volume after absorption wit bes 2 oe es 99-5 99-9 
Volume after absorption with phosphorus... ..... 99.5 99-9 
Volume after absorption with ammoniacal cuprous| 
MOE ka ce tas eva eee de 84.4 85.0 
Volume 66 00,5 is. isis ie a 15.1 nite 
