My grandfather chewed tobacco, as did his brothers and sons, all of whom worked in the coal mines of Southwest Virginia. One of my uncles, a miner, told me that it kept their mouths from getting dry and dusty. I don't think it did anything for their lungs, as several of them died from black lung. On the lighter side, my great aunt also chewed tobacco. Unless she was trying to keep flour dust out of her lungs while baking, I suspect her chewing was just a bad habit picked up from her hubby. It might even have been self-preservation! Diana Mason