436 ONE OF THE CAUSES OF DEATH UNDER CHLOROFORM. 



'langerous thing ; and a full dose prevents any risk from this 

 reflex stoppage of the heart. Tor the small dose acts on the 

 cerebral hemispheres first, and destroys the reflex action, whicli 

 contracts the vessels, while it leaves the ganglia at the base of 

 the brain and the medulla unaffected, and thus allows the reflex 

 stoppage of the heart to go on as usual. A full dose, on the 

 other hand, affects not only the cerebral hemispheres, but the 

 ganglia and medulla, and prevents any reflex action whatever 

 on the heart. I have found that, when a full dose of chloro- 

 form has been given ta a rabbit, one may hold either strong 

 ammonia or glacial acetic acid before the nose, and not the 

 slightest slowness in the beats of the heart can be observed. 

 Sometimes, indeed, it has seemed to beat rather more quickly 

 than before. 



Now let us try to apply these observations on the lower 

 animals, and, by them, try to explain the action of chloroform 

 on man, and the danger of employing it in the extraction of 

 teeth, as well as in other slight but painful operations. For it 

 is precisely in these slight but painful operations — extraction 

 of teeth and evulsion of nails — that death most frequently 

 occurs ; and it is just in them that little chloroform is given, 

 because the administrator thinks : " Oh, the operation won't 

 last above a few seconds ; and it is no use giving the patient 

 enough to keep him or her snoring for half an hour." We 

 know perfectly well that many and many an one has teeth 

 drawn under chloroform without any bad result ; and we have 

 already seen that every rabbit has not the same liability to 

 reflex stoppage of the heart from irritation of its fifth nerve ; 

 but every now and then we meet with a peculiarly sensitive 

 animal, and every now and again we meet with a case of death 

 from the extraction of a tooth under chloroform. 



If the nervous system in man be at all like that of the rabbit, 

 the violent irritation of the fifth nerve caused by the extraction 

 of a tooth will tend to stop the heart. But it will also cause 

 contraction of the blood-vessels; and thus extraction of a tooth 

 in the waking state is rarely attended with any serious con- 

 sequences. But if the reflex action on the blood-vessels, which 

 usually occurs in the cerebral hemispheres, be prevented by a 



