Sir yagadis Bose 35 



But Sir Jagadis has gone farther than this. We all 

 know the effect of great cold on our own bodies, which 

 grow numb. If your hand is half -frozen you may cut it 

 badly without feeling the pain. Then as regards animals, 

 creatures such as hedgehogs lie all the winter in a sleep 

 that resembles death. Sir Jagadis has proved that 

 metals, like animals, are most sensitive at temperatures 

 characteristic of summer, while in frost or in great heat 

 their sensitiveness rapidly diminishes. More wonderful 

 still, he has shown that metals are affected by stimulants 

 and by narcotics. A dose of bromide puts the human 

 brain to sleep and a dose of bromide of potassium adminis- 

 tered to a block of tin makes it lose much of its normal 

 sensitiveness. 



The parallel between man and metals has been carried 

 even farther. A large dose of opium deadens all the 

 human senses, but a small dose makes them more active. 

 Metals react in a corresponding way. 



More marvellous still, metals can be killed by poison, 

 like animals. A piece of metal in a healthy condition was 

 taken and tested ; the galvanometer showed that it was 

 in full vigour. Then it was treated with a dose of oxalic 

 acid, a strong poison. At once there was a spasmodic 

 flutter, then the galvanometer signals grew more and 

 more feeble, until they almost ceased. A powerful anti- 

 dote was applied, and slowly the metal began to recover 

 and to record again. The metal was given a rest, and soon 

 recovered its normal activity. 



Then the experiment was carried out a second time, the 

 metal being kept in the bath of poison until the signals 

 ceased altogether. The metal was then taken out and the 

 antidote applied. It was too late. The metal had been 

 killed. Sir Jagadis varied the experiment by using other 

 metals, but in each case the result was the same. 



This is a very strange thing, for apparently, of course, 

 the poison affects only the outside of the metal, by 



