THE POISONOUS EFFECTS OF 
CIGARETTE-SMOKING. 
I!Y Is.'"' 
WILLIAM L. DUDLEY, M.D., 
PROFESSOR OF CHEMISTRY IN THE VANDERBILT UNIVERSITY, NASHVILLE, TENN. 
FROM 
THE MEDICAL NEWS, 
September 15, 1888. [Reprinted from The Medical News, September 15, 1888.] 
THE POISONOUS EFFECTS OF CIGARETTE- 
SMOKING. 
By WILLIAM L. DUDLEY, M.D., 
PROFESSOR OF CHEMISTRY IN THE VANDERBILT UNIVERSITY, 
NASHVILLE, TENN. 
The fact that cigarette-smoking produces physio- 
logical effects differing to some extent from those of 
the cigar has led me to make the experiments which 
I record here, tending toward an explanation of it. 
The frequently ascribed cause of the difference: 
that of the adulteration of cigarrette tobacco with 
opium and other drugs and also the presence of 
arsenic in the paper are for many reasons unsatis- 
factory and insufficient. It is true, no doubt, that 
the tobacco in many of the less expensive brands is 
adulterated with cheap drugs and artificial flavors 
and that in the more expensive grades opium may 
be used; but I believe it to be equally true that 
many cigarettes are made of tobacco which is free 
from sophistication. The presence of arsenic in the 
paper is entirely out of the question. 
Before describing the experiments in detail, I shall 
discuss “smoking” in general. In “smoking” it 
is, of course, necessary that the tobacco should 
undergo combustion to a greater or less degree. 2 
DUDLEY, 
The principal elements found in tobacco are carbon, 
hydrogen, nitrogen and oxygen, and, of these, the 
carbon and hydrogen are combustible, while the 
nitrogen and oxygen are non-combustible. 
Besides combustion, destructive distillation takes 
place in the pipe, cigar or cigarette, as the result of 
the heat and the exclusion of the oxygen of the air 
which has been completely used up in passing 
through the red-hot burning tobacco, in front of 
that which the fire has not yet reached. The pro- 
ducts of this destructive distillation are ammonia, a 
yellow and very poisonous substance of disagreeable 
odor, called nicotianine, some nicotine (but most of 
the latter has been destroyed by the heat) and many 
other products of minor importance. 
The result of the combustion of the hydrogen re- 
ferred to previously is water; and the products of 
the combustion of the carbon are carbonic acid gas, 
or carbon dioxide, and carbonic oxide, or carbon 
monoxide. Carbon dioxide is the result of the com- 
plete combustion of carbon, and carbon monoxide 
is the result of the semi-combustion of carbon. 
What is known, then, as tobacco smoke is a mix- 
ture of the products of combustion and of destructive 
distillation of the tobacco with the nitrogen of the 
air. The products of the combustion of the carbon 
predominate, if measured by volume, and of these 
carbon monoxide is in excess of carbon dioxide for 
the following reason: When carbon is burned in an 
excess of oxygen the result is carbon dioxide, and 
when this carbon dioxide comes in contact with red- 
hot carbon it is deoxidized and carbon monoxide is EFFECTS OF CIGARETTE-SMOKING. 
3 
formed. This is seen in the combustion of char- 
coal, coke or anthracite in a grate or stove; the air 
passes through the grate bars and comes in contact 
with the red-hot carbon and carbon dioxide is 
formed; this gas is impelled by the draught to pass 
through the bed of glowing coals, and, in so doing, 
it is reduced to carbon monoxide, which, when it 
reaches the top, encounters a draught of air and 
burns with a pale blue, lambent flame, becoming 
oxidized to carbon dioxide again. This is similar 
to what takes place at the end of a cigar or ciga- 
rette or in a pipe, where there is a layer of fire from 
to -jig- of an inch in thickness, and as the air 
is drawn through it, carbon dioxide is first formed ; 
on passing through the hot carbon this is reduced to 
carbon monoxide, and, as such, it is drawn into the 
mouth, for when it passes beyond the fire there 
is no air or oxygen to convert it back to carbon 
dioxide. 
Now let us consider the properties of these pro- 
ducts of the combustion of carbon : carbon dioxide 
will neither burn nor support combustion. It fails 
to support life, but is not poisonous; it simply pro- 
duces death by suffocation. On the other hand, 
carbon monoxide does not support combustion,.but 
burns with a pale blue flame. It fails to support 
life because it is extremely poisonous, and this is 
due to the affinity which it has for the hemoglobin 
of the blood. It has the power to expel all of the 
dissolved and loosely combined oxygen from the 
blood, and it converts the oxyhemoglobin into car- 
bonic-oxide-hemoglobin, which, of course, results 4 
DUDLEY, 
in death. The blood thus affected acquires a florid 
arterial hue, which differs from the normal color of 
the blood by its persistence. An animal plunged 
into an atmosphere of carbonic oxide, dies instantly, 
and, when small quantities mixed with air are 
breathed, headache, giddiness and insensibility 
readily occur. Death from carbonic oxide is easily 
proved by a spectroscopic examination of the blood 
of the victim. 
There is a difference in the methods of smoking a 
cigarette and a cigar or pipe. In the two last-men- 
tioned, the smoke is simply drawn into the mouth 
and expelled directly therefrom or through the nose, 
while the experienced cigarette-smoker will inhale 
the smoke—that is, draw it to a greater or less extent 
into the air-passages and in some cases to the greatest 
depth of the lungs, and thus the absorption of the 
carbonic oxide and other gases will take place very 
rapidly, causing more or less deoxidation of the 
blood and thereby impairing its power to build up 
the wasting tissues of the body. 
Acting upon this theory I proceeded to experi- 
ment on animals and obtained for the purpose some 
mice. The animal to be experimented with was 
placed in a glass bell-jar, into which the smoke of a 
cigarette mixed with air could be drawn as rapidly 
as desired by means of a laboratory aspirator. 
In the first experiment the smoke was purified as 
much as possible, and the atmosphere breathed by 
the animal was practically oxygen, nitrogen and car- 
bonic oxide. The apparatus employed is shown in 
the accompanying figure. EFFECTS OF CIGARETTE-SMOKING. 
5 
The cigarette F was loosely inserted in the end of 
the tube E having two bulbs. D and C are bulbs 
containing a solution of potassium hydrate to absorb 
the carbon dioxide and any acids or condensable 
bodies not deposited in E. B is a tube containing 
solid potassium hydrate broken into small lumps, 
which retained any carbon dioxide that may have 
escaped the bulbs C and D. The animal was placed 
in the bell-jar and the apparatus connected together 
as shown in the figure. The aspirator, which was 
connected with the rubber tube leading from A, was 
turned on so as to draw a slow current of air through 
the apparatus in the direction indicated by the arrow. 
The cigarette was then lighted and in twenty-two 
minutes the animal was dead. 
On examination of the blood of the animal by the 
spectroscope it was found that all of the oxyhemo- 
globin had been converted into carbonic-oxide- 
hemoglobin, which showed that carbonic oxide was 
the cause of the death. This experiment was re- 
peated and the result was the same; the animal died 
in twenty-five minutes, and the spectroscope revealed 
the same condition of the blood. 
A third experiment was made without the bulbs 
C and D and the tube B. The tube E, carrying the 6 
EFFECTS OF CIGARETTE-SMOKING. 
cigarette F, was connected directly to A, and thus 
the smoke was drawn into the bell-jar without the 
removal of any of its original constituents. In this 
case the animal died in six minutes, and the exami- 
nation again showed that the carbonic oxide was the 
immediate cause of death, proving that it was the 
most noxious constituent of the tobacco smoke. 
The time required to produce death in the last ex- 
periment was about one-fourth that required in the 
first and second. This was probably due to the fact 
that in the latter the smoking was done more rapidly 
than in the preceding, owing to the lessened resist- 
ance in the apparatus and the difficulty encountered 
in reducing the force of the aspirator. In each case, 
however, the amount smoked up to the time of 
death was about the same, one and one-fourth 
cigarettes. 
From these experiments I feel justified in drawing 
the following conclusions: 
1. That carbonic oxide is the most poisonous con- 
stituent of tobacco smoke. 
2. That more injury results from cigarette than 
cigar- or pipe-smoking, because, as a rule, the smoke 
of the former is inhaled. 
3. That cigarette smoking without inhaling is no 
more injurious than pipe- or cigar-smoking. 
4. That the smoke of a cigar or pipe, if inhaled, 
is as injurious as cigarette smoke inhaled. 
5. That the smoke from a Turkish pipe, if in- 
haled, is as injurious as that of a cigarette inhaled. 
In these experiments I was ably assisted by Mr. 
W. J. Pulley, who was at the time doing special 
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