My mother told me that when she was a girl in1920's Birmingham, mothers whose children had respiratory ailments like Whooping Cough (no inoculations then !) were often told by the doctor to take them to the nearest gasworks where they should inhale the fumes which supposedly had a beneficial effect.
Apart from the derived benefit of a 4 mile walk to get there and back, does anyone have any idea what the basis was for this advice and whether there was any solid scientific rationale for it ?
I don't know when they stopped making them, but I'm pretty sure you could still buy Wrights Coal Tar Vapourisers to use at home in the 1970s for relief of respiratory problems, whether they worked I've no idea but the theory must be the same as the trip to the gasworks.