1909] on Means of Saving Life in Coal Mines. 481 



breathe, the person affected feels weak and drops down nnconscious, 

 never to recover consciousness again. The mode of resuscitation is 

 that given to drowning men. Fresh air must be artificially forced 

 into the lungs, and oxygen administered. An apparatus has been 

 invented for forcing oxygen into the lungs by pressure, so as to enable 

 the hemoglobin that has not been poisoned, and the blood serum to 

 absorb oxygen, when the poison is gradually expelled and the patient 

 recovers. 



In the case of the Tylerstown bodies there was often an extra- 

 ordinary appearance of life : the lips were pink, and in only a few 

 cases was there the paleness of death. 



Exactly similar results w^ere found with the horses which had 

 been killed. 



I remember asking Dr. Haldane whether it would be possible to 

 invent a machine capable of detecting carbon monoxide, so that 

 rescue parties going down into a mine would be w^arned w^hen there 

 was danger. 



Shortly afterwards he pointed out that nature has provided us 

 with a machine of the greatest delicacy, namely a mouse. So rapid 

 is the circulation of these little creatures, that an atmosphere w^hich 

 would take 30 minutes to affect a man, will cause a mouse to become 

 helpless in about 3 minutes. So that now mice are always kept at 

 hand at collieries for use in case of need. The men make pets of 

 them, and in one case a miner refused to let his mouse go down 

 saying that he did not mind going himself, but he was not going to 

 have his mice poisoned ! 



It is a curious circumstance that after colliery explosions mice are 

 found uninjured. After the Hemstead disaster a mouse was brought 

 up by one of the rescue party. AVe intended to give him to Dr. 

 Haldane to see if long life in a very fiery mine had made him and 

 his kin immune to the poison : but he slipped out of his cage, and 

 disappeared behind the wainscot, and there was no time to attend to 

 him further. It is said that some mice resist the poison much more 

 than others : it is therefore desirable to take several down. The 

 orders are that when one is affected the party should return, and the 

 mouse usually recovers. 



A very small proportion of after-damp is poisonous, for the affinity 

 of haemoglobin for carbon monoxide is 250 times as great as for 

 oxygen, so that the action is cumulative. About ' 2 per cent, of 

 carbon monoxide in air will cause 67 per cent, of the haemoglobin to 

 become saturated, and helplessness would ensue and probably death. 

 It requires a volume of a pint of carbon monoxide to be absorbed 

 into a man to cause death, and hence with ^ per cent, of carbon 

 monoxide in the air, if he were at rest, he might live an hour. If he 

 were in motion, as the breathing is much deeper, 25 minutes or half 

 an hour w^ould suffice. Though death from this poison is painless 

 recovery is unpleasant, being accompanied by sickness and headache. 



