the latter seems to be the case. Some scientists
have, tentatively, indicted tobacco. But a tremen
dous gap exists between such tentative indictment
and a full-scale conviction shared by all scientists.
This doesn’t mean that you ought to sit back and
laugh if your doctor suggests that you cut down
on smoking. Tobacco—like fat foods, lean foods,
exercise, lack of exercise, too much sunshine, too
little sunshine, and a host of other factors—may
be undesirable from a health standpoint for some
individuals in certain circumstances. On the other
hand, if you have nothing much wrong with you,
tobacco—despite all the scare stories—probably is
the one indulgence least likely to send you reel
ing toward the hospital or the grave.
Let’s consider the case the scientists have been
making out for—and against—the theory that
smoking causes lung cancer. This line of thought
has come particularly to the fore with the recent
simultaneous publication of two elaborate reports
in the widely circulated Journal of the American
Medical Association.
In one of these studies Drs. Ernest L. Wynder
and Evarts A. Graham, of St. Louis, compared the
smoking habits of 605 men with lung cancer
against the smoking habits of 780 other male hos
pital patients. Among the lung cancer patients
they found that 96.5 per cent had been moderately
heavy to chain smokers for many years. Among
their "control group” they reported only 73.7 per
cent who were moderately heavy to chain smokers.
CLASSED AS A CAUSE OF LUNG CANCER
Drs. Graham and Wynder put their evidence
before mathematics professor Paul R. Rider, who
reported that the difference was statistically sig
nificant. Thus these researchers concluded that
"excessive and prolonged use of tobacco, especially
cigarettes, seems to be an important factor in the
induction of bronchiogenic carcinoma,” or cancer
of the lung.
Immediately following the Graham-Wynder ar
ticle there appeared another, by Drs. Morton L.
Levin, Hyman Goldstein and Paul R. Gerhardt, of
the Bureau of Cancer Control of the New York
State Department of Health. They compared the
smoking habits of 1,045 male cancer patients with
more than 600 male noncancer patients who had
been hospitalized at the Roswell Park Memorial
Institute. And they reported that "cancer of the
lung occurs more than twice as frequently among
those who have smoked cigarettes for 25 years
than among other smokers (those who have
smoked for a shorter period of time) or non-
smokers of comparable age.”
At first glance, these reports seem to provide
substantial evidence of a close link between smok
ing and the development of lung cancer. But
other experts, both practicing cancer specialists
and cancer research workers, seriously challenge
both the statistics and the basic assumptions upon
which both the Graham-Wynder and the Levin re
ports rest.
Both reports are based, in the first place, on the
assumption that tobacco smoke contains some
agent capable of causing cancer. This view first
won favor, some years ago, when the late Pro
fessor A. H. Roffo, of the University Institute of
Experimental Medicine, at Buenos Aires, identi
fied what he believed to be cancer-causing hydro
carbons in tobacco tars. He reported consistently
positive results, using these tars, in inducing can
cer in laboratory animals.
But more recent research by Drs. E. Ashley
Cooper, F. W. Mason Lamb, E. L. Hirst and Edgar
Sanders, all of the University of Birmingham, Eng
land, and by Drs. Otto Schurch and Alfred Winter-
stein, of a research unit if Zurich, Switzerland, has
failed to duplicate the results Dr. Roffo claimed.
At the National Cancer Institute in Bethesda,
Maryland, this country’s leading basic cancer re
search center, similar attempts have also provided
negative results.
In one long series of experiments, for example,
Public Health Service research workers took two
substantial groups of cancer-susceptible laboratory
mice. One group was kept in a smoke-free cham
ber. The other was exposed to heavy tobacco
smoke for at least half its normal life-span. After
10 months of constant exposure, the smoke-eating
mice remained as tumor-free as their brothers and
sisters in the control group.
Then the Public Health Service researchers went
even further. They injected tobacco tars into mice
of cancer-susceptible strains. They dissolved the
tars in the drinking water of other mice. They
put the tars under the skins of still other mice.
Despite these massive exposures, their mice
failed to develop cancer. Tobacco tars, if canceri-
genic at all, were demonstrated clearly to be far,
far less so than coal tars and many other agents
to which many industrial and mining workers are
frequently exposed.
Drs. Graham and Wynder lay great stress, in
their report, upon the fact that both cigarette
smoking and lung cancer have apparently increased
along parallel lines. "From the evidence pre
sented,” they state, "the temptation is strong to
incriminate excessive smoking, and in particular
cigarette smoking over a long period, as at least
one important factor in the striking increase of
bronchiogenic carcinoma.”
Cancer researchers of the National Cancer In
stitute, however, take sharp issue with this point
of view. They concede that i r surveys show a
marked increase in lung cancer. But Dr. Austin
V. Deibert, chief of the Cancer Control Branch of
the National Institute of Health, pointed out in a
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