492 ASPHYXIA. [BOOK u. 



by the fact that they fail to make their appearance when the 

 spinal cord has been previously divided below the bulb, though 

 they still occur after those portions of the brain which lie above 

 the bulb have been removed. It is usual to speak of a ' con- 

 vulsive centre ' in the bulb, the stimulation of which gives rise 

 to these convulsions ; but if we accept the existence of such a 

 centre we must at the same time admit that it is connected by 

 the closest ties with the normal expiratory division of the res- 

 piratory centre, since every intervening step may be observed 

 between a simple slight expiratory movement of normal respira- 

 tion and the most violent convulsion of asphyxia. An addi- 

 tional proof that these convulsions are carried out by the 

 agency of the bulb is afforded by the fact that convulsions of a 

 wholly similar character are witnessed when the supply of blood 

 to the bulb is suddenly cut off by ligaturing the blood vessels 

 of the head. In this case the nervous centres, being no longer 

 furnished with fresh blood, become rapidly asphyxiated through 

 lack of oxygen, and expiratory convulsions quite similar to 

 those of ordinary asphyxia, and preceded like them by a pass- 

 ing phase of dyspnoea, make their appearance. Similar ' anaemic ' 

 convulsions are seen after a sudden arid large loss of blood from 

 the body at large, the bulb being similarly stimulated by the 

 lack of arterial blood. In ordinary fainting, which is loss of 

 consciousness due to an insufficient supply of blood to the brain, 

 the diminution of blood supply is not great enough to produce 

 these convulsions. 



Such violent efforts speedily exhaust the nervous system ; 

 and the convulsions after being maintained for a brief period 

 suddenly cease and are followed by a period of calm. The calm 

 is one of exhaustion ; the pupils, dilated to the utmost, are 

 unaffected by light ; touching the cornea calls forth no move- 

 ment of the eyelids, and indeed no reflex actions can anywhere 

 be produced by the stimulation of sentient surfaces. All expi- 

 ratory active movements have ceased ; the muscles of the body 

 are flaccid and quiet ; and though from time to time the respir- 

 atory centre gathers sufficient energy to develop respiratory 

 movements, these resemble those of quiet normal breathing, in 

 being, as far as muscular actions are concerned, almost entirely 

 inspiratory. They occur at long intervals, like those after sec- 

 tion of the vagi ; and like them are deep and slow. The 

 exhausted respiratory centre takes some time to develop an 

 inspiratory explosion ; but the impulse when it is generated is 

 proportionately strong. It seems as if the resistance which had 

 in each case to be overcome was considerable, and the effort in 

 consequence, when successful, productive of a large effect. 



Very soon, these inspiratory efforts become less frequent ; 

 their rhythm becomes irregular ; long pauses, each one of which 

 seems a final one, are succeeded by several somewhat rapidly 



