122 PATHOLOGY. 



the cliest and the aeration of the blood cease also. The post 

 mortem appearances of death by coma and of that by apncea are 

 the same, except, indeed, in those cases where the cause of the 

 coma remains, when it will be present in addition to those of 

 apncea. Reasoning upon the conclusion that the circulation 

 ceases consequent upon the cessation of the act of respiration, 

 arising from suspension of the nervous power, Sir Benjamin 

 Brodie was led to think that by continuing respiration artifi- 

 cially in animals labouring under narcotic poisons, the circulation 

 of the blood might be kept up until the effect of the poison upon 

 the brain had passed off. The correctness of the supposition he 

 soon verified by experiment. He inserted some woorara into a 

 wound which he had made in a young cat : this after a short 

 time entirely destroyed the respiratory movements, and the 

 animal appeared to be dead, but the heart could still be felt 

 beating. The lungs were then artificially inflated about forty 

 times a minute. The heart continued to beat regularly. When 

 artificial respiration had been kept up for forty minutes, the 

 pupils of the cat's eyes were observed to contract and dilate 

 upon the increase and diminution of light, but the animal 

 remained perfectly motionless and insensible. At the end of an 

 hour and forty minutes there were slight involuntary contrac- 

 tions of the muscles, and every now and then there was an effort 

 to breathe. At the end of another hour the animal, for the first 

 time, showed some signs of seusibiKty when roused, and made 

 spontaneous efforts to breathe, twenty-two times in a minute. 

 The artificial breathing was, therefore, now discontinued. It 

 lay as in a state of profound sleep for forty minutes longer, 

 when it suddenly awoke and began to walk about. It must 

 be clearly understood that artificial respiration can be beneficial 

 only where there is a suspension of the nervous functions, as in 

 cases of poisoning, and not wliere there is destruction of them 

 by disease, injury, or the long-continued action of poisons. 



Professor Sewell experimented upon the horse with the 

 woorara poison, and found that by artificial respiration life 

 could be maintained until the action of the poison had passed 

 away, and that afterwards the animal regained consciousness 

 and recovered from its effects. 



