The commentary also doubles as a synopsis, and is therefore reproduced in full:

Twenty years ago it was asthma, or miner's cough. In 1931, it became silicosis, and you could get compensation. In 1943 it became pneumoconiosis - dust disease. What is it, and what are the doctors doing about it?

Not only miners breathe in dust. Most people who live in cities take in an enormous quantity daily. In the bloodstream of our lungs, special dust cells carry away the dust.

But coal dust in some pits, especially the anthracite and steam-coal pits of South Wales, is too much for the dust cells. They can't carry all of it away. Some of the dust accumulates in parts of the lungs, and these parts are damaged. And the other parts of the lungs have to work harder and, in a very few years, are worn out.

At Llandough Hospital near Cardiff, a team of doctors have been working on the problem of dust disease. On X-ray plates, they can see it, but are still seeking a way to cure it once it has gained a hold.

But it need never gain a hold at all, if only a routine check can be made of all miners. Here are some of the methods of checking. Miners are X-rayed at regular intervals. Just as regularly, their chest expansions are measured. With more complicated apparatus, the vital capacity of each man, his ability to breathe in air and get oxygen out of it, can be measured.

The doctors have won the first round. They have taken the mystery out of dust disease, and know what they're fighting. They can now recognise the first signs, and take the miners out of danger before they get it too badly. Under their director, they will work on until they find a cure for those already disabled.