16 JULY 1954, Page 14

SIR,—lf we define smoke as suspended par- ticles in air,

then anyone who works in a vitiated atmosphere or walks through fog inhales smoke with every breath. The cigarette smoker may or may not inhale smoke with every breath, but if he breathes in a vitiated atmosphere he must inhale smoke. It seems to me that if statisticians are to assess the damage done by smoke they must have more specific data upon which to base their calculations. It .is essential that they should know what element or chemical com- pound in the smoke under investigation is under suspicion of being responsible for cancer or has a contributing effect. Is it

nicotine '? Is it nitrate or nitrites '? Is it

sulphate or sulphites ? Is it , fluorine ?- Yours faithfully,

DENTAI. SURGEON

[Tar is under suspicion.--Editor, Spectator.]