y. B. S. Haldane 107 



sible. The writer was once out fishing on Dartmoor on 

 a blazing hot day. He became extremely thirsty, and, 

 finding a spring of ice-cold water welling from the hill- 

 side, drank, not wisely, but too well. In a short time he 

 collapsed in agonizing cramp. 



About the hottest place in England is a deep coal-mine. 

 There is one under Salford nearly a mile deep, with a 

 temperature so torrid that the men work in boots and 

 bathing drawers, and drip with sweat during the whole 

 shift. It is on record that one man lost eighteen pounds' 

 weight in the course of a shift. So long as these men did 

 not drink more than a quart of water during a shift no 

 harm came to them, but if this amount was exceeded — 

 and of course it often was — they suffered from appalling 

 cramp, sometimes in the stomach, sometimes in the back 

 or shoulders. The reason, as explained by Mr Haldane, 

 was that they had taken too much water for the salt 

 concentration in their blood. Blood, as we all know, is 

 as salt as sea-water, and large amounts of fresh water 

 alter its content. 



The miners were then provided with drinking-water in 

 which a certain amount of salt had been dissolved. To 

 anyone less thirsty than they it would have been a nasty 

 beverage, but they drank it by gallons and asked for more. 

 And now there is no more cramp and very much less 

 fatigue. The cramp of stokers, and of gas- and iron- 

 workers, can be prevented in the same way. 



J. B. S. Haldane is a bio-chemist — not a doctor, but 

 one who takes a part in developing or creating remedies 

 for diseases. As he says himself, a bio-chemist provides 

 chemical splints for damaged organs. Now most people 

 have an idea that all drugs are tried out upon animals 

 such as dogs, rabbits, guinea-pigs, and rats. It would 

 surprise them to learn how often the chemist tries 

 experiments on himself, how often he acts as his own 

 rabbit. 



