14 MISCELLANEOUS PAPERS. 
cance. Among the more easily condensible constituents may be men- 
tioned nicotine and its decomposition products, especially pyridin, 
an ethereal oil of fragrant odor and a complex mixture of thick, tarry 
substances. Of course the smoke also contains large quantities of 
carbon dioxid and water vapor resulting from the combustion of the 
tobacco. The nicotine content of tobacco smoke has been extensively 
studied by Kissling,’ whose principal conclusions may be briefly sum- 
marized as follows: Considerably less than half of the total quantity 
of nicotine is ordinarily destroyed in the smoking of a cigar, and 
greater or lesser quantities enter into the smoke, depending on what 
portion of the cigar remains unsmoked. In the case of a lot of cigars 
containing 3.75 per cent of nicotine, when two-thirds of the entire 
cigar were smoked about 28 per cent of the nicotine in the smoked 
part of the cigar was contained in the smoke; about 12 per cent had 
accumulated in the unburned portion of the cigar, and about 60 per 
cent was destroyed. In another experiment in which nearly seven- 
eighths of the entire cigar. were smoked, the percentages were 52, 5.5, 
and 42.5, respectively. Unfortunately, in these tests the cigars were 
smoked by drawing through them a constant flow of air instead 
of by intermittent “ puffs,” as in the actual practice of smoking, 
so that the above values are not entirely applicable. Kissling con- 
siders that the physiological effects of tobacco smoke are produced 
almost wholly by nicotine and its immediate decomposition products 
of the pyridin class of compounds. 
We have carried out several experiments along the lines of those 
conducted by Kisshng to determine more particularly the effects 
produced by citric acid on the nicotine content of tobacco smoke. A 
portion of the sample of tobacco repeatedly referred to in this paper 
was sprayed with an aqueous solution of citric acid in the manner 
already described, and was then made into cigars. Another portion. 
of the same sample without the addition of the acid was also made 
into cigars. A lke number of each was smoked in a suitable ap- 
paratus, the smoke being drawn through a series of flasks containing 
sulphuric acid to absorb the nicotine. The wash waters containing 
the nicotine from the smoke were then distilled in a current of steam 
to remove any indifferent volatile matter, an excess of alkali added, 
and the mixture was then again distilled. The distillate containing 
the nicotine mixed with pyridin and a relatively large amount of 
ammonia was accurately neutralized with sulphuric acid and then 
evaporated to dryness. The nicotine and pyridin were then separated 
from the ammonia by extracting the residue with small volumes of 
absolute aleohol. The apparatus used for smoking the cigars was so 
¢Dingl. Polyt. Journal, 1882, p. 64. 
’ The word ‘ puff” in this paper is used to cover both the inhalation ard ex- 
pulsion of the smoke. 
141—1 
