RESPIRATION 221 



incompatible with life. In the rabbit, as a rule, death takes 

 place in twenty-four hours. A sheep may live three days, 

 and a horse five or six. Dogs often live a week, occasionally 

 a month or even two, and in rare instances they may survive 

 indefinitely. The most prominent symptoms (in the dog), 

 in addition to the marked and permanent slowing of 

 respiration, quickening of the pulse and contraction of the 

 pupils, are the frequent vomiting and progressive emacia- 

 tion. The appetite is sometimes ravenous, but no sooner is 

 the food swallowed than it is rejected ; and this is par- 

 ticularly true of water or liquid food. The fatal result is 

 usually caused, or at least preceded, by changes of a 

 pneumonic nature in the lungs. The precise significance of 

 the pulmonary lesion is obscure. But it would seem that 

 paralysis of the laryngeal and cesophageal muscles, with the 

 consequent entrance of food, foreign bodies, and perhaps 

 bacteria, into the lungs, is responsible to a great extent. 

 And when only a partial palsy of the glottis is produced, by 

 dividing the right vagus below the origin of the recurrent 

 laryngeal, and the left, as usual in the neck, pneumonia either 

 does not occur or is long delayed. It may be that the 

 tissue of the lungs is rendered particularly susceptible to 

 such insults in consequence of a hypersemic condition in* 

 duced by the section of pulmonary vaso-motor fibres in the 

 vagi. The vomiting is certainly connected with the paralysis 

 and consequent dilatation of the oesophagus ; and by pre- 

 viously making an artificial opening into the stomach, or by 

 a surgical prophylaxis still more heroic, the establishment 

 of a double gastric and cesophageal fistula, certain observers 

 have been able to prevent death for many months. 



Special Modifications of the Respiratory Movements. Cheyne- 

 Stokes Respiration is the name given to a peculiar type of 

 breathing, marked by pauses of many seconds alternating 

 with groups of respirations. In each group the movements 

 gradually increase to a maximum amplitude, and then 

 become gradually shallower again, till they cease for the 

 next pause. The cause is unknown. The phenomenon is 

 not peculiar to pathological conditions, although it often 

 t/ccurs in certain diseases of the brain, and although pressure 



