22 ADDRESS TO THE BRITISH ASSOCIATION, 1881. 



immunity from the fever. The interesting researches 

 of Burdon- Sanderson, Greenfield, Koch, Pasteur, Tous- 

 saint, and others, seem to justify the hope that we may 

 be able to modify these and other germs, and then by 

 appropriate inoculation to protect ourselves against 

 fever and other acute diseases. 



. Ferrier's researches in continuation of those of 

 Fritsch and Hitzig have enabled us to localise the 

 function of various parts of the brain. His results 

 have not only proved of great importance in surgery, 

 and in many cases led to successful operations by point- 

 ing out the exact source of the mischief, but an exact 

 knowledge of the brain is also of the greatest importance 

 in the treatment of nervous diseases. Echeverria has 

 collected 165 cases of traumatic epilepsy, of which 64 

 per cent, were cured by removing a portion of the 

 skull, the site for the operation and the exact locality 

 of the injury being indicated by cerebral localisation. 



The history of Anaesthetics is a most remarkable 

 illustration how long we may be on the very verge of 

 a most important discovery. Ether, which, as we all 

 know, produces perfect insensibility to pain, was dis- 

 covered as long ago as 1540. The anaesthetic property 

 of nitrous oxide, now so extensively used, was observed 

 in 1800 by Sir H. Davy, who actually experimented on 

 himself, and had one of his teeth painlessly extracted 

 when under its influence. He even suggests that ' as 

 nitrous oxide gas seems capable of destroying pain, it 

 could probably be used with advantage in surgical 

 operations.' Nay, this property of nitrous oxide was 

 habitually explained and illustrated in the chemical 

 lectures given in hospitals, and yet for fifty years the 



