486 RESPIRATION. 



ruptedj and oxygenated blood is not supplied to the tis- 

 sues. The same effect, practically, follows abstraction of 

 the circulating fluid, or the absorption of any poisonous agent 

 which destroys the function of the corpuscles as carriers of 

 oxygen ; though in hemorrhage, the effects are not as marked, 

 as generally the system is gradually debilitated by the pro- 

 gressive loss of blood. It was invariably noticed in the ex- 

 periments above referred to, that after the division of a large 

 artery, though artificial respiration was carefully performed, 

 respiratory efforts took place when the system was nearly 

 drained of blood. As the hemorrage continued, these efforts 

 became more violent, and eventuated, just before death, in 

 general convulsions. 1 A comparison of this experiment with 

 those in which artificial respiration was simply interrupted 

 shows that in sudden hemorrhage there can be no doubt that 

 the system feels the want of oxygen ; and when the loss of 

 blood is very great, this is increased until it amounts to a 

 sense of suffocation. In gradual hemorrhage, there is a con- 



1 " Expt. xxxiv., Feb. 19, 1861. A good-sized dog was etherized and the chest 

 opened in the usual way. Artificial respiration was established, and Expt. xxix. 

 verified. The blood was then allowed to flow freely from the femoral artery, 

 while artificial respiration was actively continued. While the blood continued to 

 flow, the respiratory muscles were carefully observed. During the first part of 

 the bleeding no respiratory efforts took place; but when the blood had flowed for 

 a considerable time, and the system was becoming drained, respiratory efforts com- 

 menced, feeble atflrst, but as the bleeding continued, becoming more violent until the 

 whole muscular system was affected by convulsive movements" (Am. Journ. y loc. 

 cit., p. 376.) 



Convulsions after profuse hemorrhage have long been observed by physiol- 

 ogists, but no entirely satisfactory explanation of their occurrence has ever been 

 given. There now can be no doubt that they are due to a deficiency of oxygen. 

 The experiments of Kusmaul and Tenner ( On the Nature and Origin of Epilepli- 

 form Convulsions caused by Profuse Bleeding. New Sydenham Society, London, 

 1859) show that convulsions may be produced by ligature of the great vessels 

 carrying blood to the brain. In this case they are probably due to a deficiency of 

 oxygen in this vascular and highly organized part. In their experiments, which 

 were made on rabbits, it was observed that " respiration is at first accelerated, but 

 shortly afterwards, a little while before the approach of general convulsions, it 

 becomes prolonged and deep." P. 14. 



