Sat, 10 Apr 1999 08:43 UTC
Chapter 9: Smoking Animals
Remember the smoking beagles? Movietone News, the old newsreel company, featured a piece on these cute little dogs, shot some time in the 1950's or 60's. It's sometimes re-run on late night TV, even today.
Actually, the experiment was rather cruel (although not nearly so much so as later ones). The beagles were strapped side-by-side to a long bench, in a rather unnatural upright position. They were fitted with face masks, which forced them to inhale and exhale smoke from lighted cigarettes. A mechanical device lit a new cigarette and dropped it into the air line, as soon as an old one was used up. Although the Surgeon General later claimed that the smoking machines did not force animals to inhale and exhale deeply, the newsreel footage sure made it look as if the dogs were inhaling and exhaling very deeply.
It was, perhaps, the smoking Beagles that were referred to in the 1964 SG's Report, when the Committee made the observation that with the "possible exception of dogs", the animal experiments had all failed to induce lung cancers. Whatever the case, in the 1971 Report, the Surgeon General conceded that the experiments with dogs, using smoking machines, had failed. However, also in the 1971 Report, the SG described a new experiment, conducted by a government physician, Oscar Auerbach, and others, in which the Beagles were forced to smoke in what the SG described as a "more natural" manner.
Specifically, Auerbach claimed to have slit the throats of 78 Beagles and inserted tracheotomies. He claimed that he had been able to train the dogs to smoke cigarettes through those tracheotomies. A table was presented, showing the number of dogs that managed to survive for 875 days, smoking either regular cigarettes or filter tips or no cigarettes at all. Amongst the 8 controls who did not smoke, there were no deaths. Among the smokers, however, there were 24 deaths from various causes, variously listed as "aspiration of food", lung fibrosis, etc. Although Auerbach did not claim that any of the dogs died from lung cancer, he did in fact claim that 2 of the animals, who smoked non-filter cigarettes, had developed early invasive squamous cell carcinoma in the bronchi.
Auerbach's experiment was again described and the table again presented in the 1977 SG's Report (which was just a reprint of portions of earlier reports). In the 1982 Report, however, the SG described Auerbach's experiment again but this time the SG remarked that Auerbach's "observation has not been repeated so far".
When a scientist says that an observation has not been repeated, it is a polite way of saying that the initial experiment may have been fraudulent. It would be nice to know why Auerbach's experiment was not replicated. Were others unable to train Beagles to smoke through tracheotomies, or were others able to do so, but no harm was done to the dogs? We do not know and the SG does not tell us.
At page 185 of the 1982 Report, there is a general discussion of the difficulties experienced in trying to induce cancer in laboratory animals by forcing them to inhale smoke. We are told that there's too much carbon monoxide in cigarette smoke to allow for continuous exposure, so that inhaling machines must be used. But, we are told, "laboratory animals are not willing to inhale aerosols very deeply and are especially reluctant to inhale tobacco smoke. Rhesus monkeys and baboons have been trained to smoke cigarettes. This approach does not yield neoplasms [cancers] because of insufficient exposure time and because of the tendency of the animals to puff rather than to inhale". Maybe so, but the old newsreel pictures of the smoking Beagles surely seemed to show them inhaling, deeply!
Also, at pages 185 and 186 of the 1982 Report, there is a description of some failed experiments with Golden hamsters, explaining why tobacco smoke had failed to induce lung tumors. Never-the-less, interleaved into all of these discussions of failures, there is a description of an experiment which, allegedly, succeeded. At page 185, we are told that in 1980 experimenters at the Oak Ridge National Laboratories, using a newly developed "advanced inhalation device" were able to induce tumors of the "respiratory tract" in rats. The Report states that "...seven of the 80 smoke exposed rats had tumors.." and that one of 30 "sham exposed rats" had tumors.
Apparently, the "advanced inhalation device" referred to by the SG is the "Maddox-ornl smoking machine". It is referred to in an article by A.P. Wehner, et al., which appeared in 1981 in Toxicology and Applied Pharmacology at pages 1-17. There, the authors describe an experiment in which 80 female rat were forced to consume 8 cigarettes per day, seven days per week, for 2 years. One of the rats developed a carcinoma of the lung.
Before getting too excited about these experiments, however, we need to consider this: the largest known rats weigh no more than an average of one pound. Forcing a one pound rat to smoke 8 cigarettes per day is the equivalent of forcing a 160 pound human to smoke 1280 cigarettes per day (64 packs). Such experiments are not realistic and in no way replicate exposure to ordinary tobacco smoke. Given the enormous concentrations of smoke used by the experimenters, it is wonder that any of the animals even survived the ordeal; yet, they did, and only a small percentage developed tumors.
Strangely, despite exhaustive research in medical databases, I have been unable to find any additional rat experiments (or experiments with any other animals) conducted in the years since 1980, which replicate the above reported experiments. A 1989 article in Toxicology and Applied Pharmacology, describes an experiment in which rats of both sexes were forced to inhale cigarette smoke in high concentrations for 22 weeks. The rats were then killed, and investigations made to determine the effect of the smoke on the level of "DNA adducts". The experimenters concluded that "inhaled cigarette smoke induces lung DNA adducts which may play an important role in cigarette smoke-induced lung carcinogenesis" (emphasis mine). But the experimenters stopped short of claiming that the smoke actually induced any tumors.
A report of a similar experiment with rats forced to smoke for 8 weeks appears in 1985 in the Journal, Cancer Research. Here again, however, the researchers did not claim that the smoke did the animals any direct harm. They claimed, instead, that the smoke reduced the level of production of cytotoxin, a substance thought to be toxic to certain types of tumor cells. My question is simply this: why haven't the 1980-81 rat experiments been repeated? Was there something wrong with them? Did the researchers conclude that because of the extremely high concentrations of smoke given to the animals, and the large number of animals that were unharmed, the experiments failed to prove their point? Or was there some other reason? I'm afraid I don't have the answers.
In recent years, new smoking machines have been devised that subject rats to second hand smoke. In an article in the May 28, 1994 issue of The Los Angeles Times, writer Sheryl Stolberg describes experiments that have been going on for three years, exposing rats to continuous concentrations of smoke as high as 4,000 micrograms per cubic meter, concentrations many times the concentrations encountered in the real world, even in times of brief exposure, e.g., bars. Bottom line: no significant harm to the animals has been shown, although one researcher at UC (Davis) claims a 6% reduction in birth weight for the offspring of the exposed animals.
In earlier versions of this book, I left the subject of the animal inhalation experiments with unanswered questions. It appeared that there had been two experiments - never repeated - one of which induced a single carcinoma in a rat, and other of which supposedly induced "tumors" in a very small percentage of rats. In 1998, however, an event took place which enables me to resolve the unanswered questions. In that year, the State of Minnesota brought a lawsuit against tobacco companies to recover damages to the State, allegedly caused by smoking. The case was settled before any judgment could be rendered, but not before a few trial sessions were held.
At these sessions, testimony was taken from experts for both the plaintiff (the State) and the Defendants (the tobacco companies). Experts for both sides agreed that, despite many, many animal inhalation experiments over a period of many years, all of the experiments had failed, i.e., nobody has ever been able to demonstrate, through animal experiments, that inhaling tobacco smoke - no matter in what quantities or concentrations - causes lung cancer. These failures are powerful evidence, indeed. If, as alleged, smoking causes lung cancer, training or forcing animals to smoke should produce lung cancers. It doesn't.
Before leaving this subject, I ran into a couple of strange, weird studies while doing the research on smoking animals. A 1993 study in Norway reminds me of an old joke about a temperance lady who comes to a school to do a demonstration. She has a worm, a glass of water and a glass of booze. She drops the worm into the water and it swims about unharmed; then she drops the worm into the glass of booze and it instantly shrivels up and dies. She asks the class, "Can anyone tells me what this means?". Little Johnny holds up his hand and shouts "It means that booze is mighty good for you if you have worms!".
Anyway, in the Norwegian study, investigators induced pneumonitis (lung inflammation) in rats by exposing the animals to radiation. The animals were then exposed to tobacco smoke, and it was shown that the smoke actually suppressed the inflammation in the lungs. In short, smoking is good for you if you have pneumonitis (I guess).
The other weird study has little to do with smoking; I simply report it because it's interesting. Recently, health food stores have begun selling green tea, because of its alleged health benefits. In fact, some have suggested that the drinking of green tea accounts for the low rate of lung cancer in Japan and China. A study published in 1990 in Environmental Research, however, claims exactly the opposite. According to that study, females in Hong Kong had a 2.7 times greater risk of developing lung cancer if they drank green tea than if they did not drink green tea. This just proves that you can prove anything with statistics, which is another way of saying you can't prove anything with statistics.