Smoking: It Is Less Hazardous

Ever since Dr. Ernest L. Wynder began trying to convince the world of the dangers of cancer in cigarette smoking, he has looked as cheerful as a basset hound being dragged through a cactus patch. Last week he looked as sad-eyed as ever, but he had good news for smokers. Cigarettes, he told the American Association for Cancer Research, have been made " less hazard ous" — he would not say "safer" — in the last few years, and they are being made still less hazardous.

It may take years for these improve ments to show up in a lower death rate from lung cancer. But figures compiled at the National Cancer Institute indi cate that while lung cancer is still increasing, it is doing so less rapidly.

Mouse Backs. Dr. Wynder, who has never smoked, began work on cigarettes and cancer while still a medical student in St. Louis. Now at Manhattan's Sloan-Kettering Institute for Cancer Research, working with Chemist Dietrich Hoffmann, he has had tens of thousands of cigarettes smoked in machines, collected the vapors and "tar," and tested innumerable fractions as potential causes of cancer. Most early tests were on the backs of mice be cause the skin there is of the same cellular class as the inside of a man's lung. More recently, to study an approximation of what happens when smoke rushes past the tiny, hairlike filter system (cilia) of the human respiratory tree, the researchers have taken to using parts of the gills of hard-shell clams.

The first big gain, Drs. Wynder and Hoffmann find, comes from filters. "The smoker of filter cigarettes of 1964 is on the average exposed to approximately 50% less tar*and nicotine than he was while smoking cigarettes without filter tips ten years ago," they reported. Contrary to gloomy prophecies that smokers would cancel out the benefits of filters by puffing more of the newer cigarettes, the researchers found that in general this has not happened.†

The components of smoke that paralyze the cilia, and are therefore important in bronchitis and related diseases, are largely carbolic and other acids. A proportion of these (up to 90% in the case of phenol) can be removed by cellulose acetate filters. Other cilia-damaging components, such as acetaldehyde and acrolein, are cut down by an activated charcoal filter, especially if the charcoal is compressed. A still better way, said Wynder and Hoffmann, is to filter the smoke through water and then through compressed charcoal, but so far this is not practicable —except, conceivably, in homes with filter-tipped hookahs.

Back to Old Ways. Even cigarettes without filters are less hazardous nowadays. The researchers learned this in an odd way: fewer of their test mice have been developing cancers. At first they thought this might be caused by a difference in mice or in laboratory methods. Then they learned that it was because manufacturers are using different types of tobacco.