SYMPTOMS OF CARBON MON-OXIDK POISONING. 45 



ferer should take warning- from the preliminary symptoms. 

 When 0.06 per cent. CO is present in the air it will cause the 

 blood to accumulate 30 per cent, after an hour and a half: 0.1 

 per cent- causes helplessness in about an hour : with 0.3 per 

 cent, the blood will be saturated in half an hour; with one 

 per cent, saturation of the blood takes place in five or six 

 minutes. Characteristic of death by carbon mon-oxide is the 

 rose-red life-like appearance of the corpse; before death, how- 

 ever, the skin is dusky except where more or less extended 

 patches of bright colour make their appearance on the body, 

 while the lips and extremities are blue. After death the eyes 

 are bright and staring, the pupils dilated, and the jaws fixed. 

 It takes a considerable time to get rid of carbon mon-oxide 

 from the blood, which is probably done by converting it into 

 carbon dioxide ; if a man has absorbed much into his system, 

 resuscitation may be impossible. The removal of carbon mon- 

 oxide from the blood proceeds five times as rapidly with pure 

 oxygen as with fresh air, according to Dr. Haldune*. The 

 amount of oxygen to be inhaled by a person necessarily de- 

 pends on the quantity of carbon mon r oxide absorbed. Dr. 

 Haldane recommends the breathing of oxygen for an average 

 of 10 minutes, which would consume about two cubic feet. A 

 rough method of obtaining oxygen in case of emergency is to 

 heat potassium chlorate, which readily yields up its oxygen. 



Mice are sometimes kept at mines for the purpose of testing 

 for CO, as they are peculiarly susceptible to its poisoning ef- 

 fects, since a mouse respires 20 times quicker than a man, and 

 consequently exhibits symptoms of blood saturation more 

 rapidly. The white variety used for pets are generally kept, 

 as they are more delicate than the ordinary mouse and are 

 more readily observed with a bad light. As soon as a mouse 

 becomes incapable of motion, due to the presence of carbon 

 mon-oxide, the air should be considered dangerous to man. 



After damp is a mixture of the gases resulting from an 

 explosion, and consists of carbon dioxide, carbon mon-oxide, 

 nitrogen and water. There are more deaths due to suffocation 

 and poison by carbon mon-oxide in after damp than to injuries 

 by violence and burns the result of an explosion. A man suffers 

 severely when recovering from poisoning by after damp, and 

 may succumb days afterwards from the effects. Drs. D. Macaulay 

 andL. Gr. Irvinet lay great stress on the fact that "gassing" is 

 a shock to the system, and that shock is characterised by three 

 important symptoms. First, weakening of the heart's action: 



^Causes of Death in Colliery Explosions, and Underground 

 Fires. London, 1896. By authority. 



tSafety Measures in Mining. (.Ton!. Chem. Met. and 

 Miu. Soc. of South Africa, Nov., 1905.) 



