READJUSTMENTS OF REGULATION. 45 



carbon monoxide poisoning. This gas (CO) is the 

 poisonous constituent of ordinary lighting gas ; and 

 poisoning with it is extremely common in America 

 on account of the high percentage of carbon monoxide 

 in the carburetted water gas used extensively as a 

 substitute for the old-fashioned coal gas still supplied 

 in England. I discovered about twenty years ago that 

 CO poisoning is also the cause of nearly all the deaths 

 in great colliery explosions and fires, and a source of 

 extreme danger to rescuers. 



Claude Bernard found that CO enters into combina- 

 tion with haemoglobin, just as oxygen does, but forms 

 a far more stable compound. In presence, therefore, 

 of sufficient CO the oxygen-carrying power of the 

 haemoglobin is suspended, and death must result from 

 want of oxygen. It was supposed that CO has also a 

 direct poisonous action on the nervous system. That 

 this is not so I succeeded in showing by placing ani- 

 mals in compressed oxygen before giving them CO. 

 In the compressed oxygen sufficient oxygen goes into 

 ordinary physical solution in the blood to enable 

 the animal to dispense with oxyhaemoglobin as an 

 oxygen carrier; and the animal remains unharmed 

 although its blood and tissues are saturated with 

 CO. Animals which do not employ haemoglobin as 

 an oxygen carrier live for weeks quite comfortably in 

 an artificial air composed of 80 per cent of CO and 

 20 per cent of oxygen. CO is not oxidised in the 

 living body, and apart from its one fatal property of 

 combining with haemoglobin it is a physiologically 

 indiflferent gas. 



