RESPIRATION 129 



and often end in death. 12 For a reason which will be explained 

 in a later chapter they are most commonly met with after CO 

 poisoning, and whatever their origin they are often grossly mis- 

 interpreted. The patient does not recover at once on removal of 

 the oxygen want, as in short exposures. In cases of CO poisoning 

 consciousness may not be recovered, although within an hour or 

 two after removal to fresh air most of the CO has already disap- 

 peared from the blood. It is exactly the same with men who have 

 remained unconscious for, perhaps, several hours in air very poor 

 in oxygen. Or if consciousness has been partially recovered the 

 patient may lapse again into unconsciousness. During gradual 

 recovery there is usually a very marked spastic condition of the 

 muscles, and occasional epileptiform seizures, and there may be 

 various partial paralyses and other nervous symptoms. Sometimes 

 the patient lingers on for weeks in a comatose condition with 

 spastic muscles and occasional opisthotonos. The body tempera- 

 ture is unstable, and every function of the central nervous system 

 seems to be more or less affected. Gross hemorrhages in the brain 

 have been described, and Mott has found small multiple hemor- 

 rhages. The symptoms are, however, evidently due in the main 

 to widespread injury to the nerve cells themselves during the ex- 

 posure. Loss of memory, mental incapacity, and even definite 

 mania may follow the exposure; but whatever the nature of the 

 symptoms may be, they nearly always pass off gradually if the 

 patient survives the first few days. One interesting nervous after 

 effect occasionally observed is what appears from the symptoms 

 to be peripheral neuritis. 



The heart may also suffer severely in prolonged exposure to 

 want of oxygen ; and if the exposure has been accompanied by 

 much muscular exertion, as in efforts to escape or to rescue other 

 men, the after symptoms may be mainly cardiac. In these cases 

 the pulse is feeble and irregular, the heart dilated, with a blowing 

 systolic murmur; and any muscular exertion produces collapse. It 

 may be a considerable time before the heart fully recovers. 



Probably every other organ and tissue in the body feels the 

 after effects of severe exposure to want of oxygen. The patient 

 often enough dies of pneumonia. Acute nephritis and gangrene of 

 extremities have been noticed as sequelae to the acute broncho- 

 pneumonia and oedema of the lungs in chlorine poisoning. As 



" An interesting description of these symptoms by Dr. Shaw Little will be 

 found in Appendix B to my Report on the Causes of Death in Colliery Explosions, 

 Parliamentary Paper C. 8112, 1896. 



