56 Professor Halford. 



The assistants in this were Dr. Neild and Dr. 

 Wooldridge. 



It will be seen that, at that time, I had no Cam- 

 bridge Artificial Respirary Pump ; but had to rely upon 

 an ordinary pair of bellows, into which, when needed, 

 I could pour chloroform, so as to produce insensibility 

 in the dog. 



To a fine large dog, chloroform was administered, 

 and when under its influence, the anterior part of the 

 sternum, and some portions of the cartilaginous ends 

 of the ribs, were removed to show the contents of the 

 thorax. Artificial respiration was kept up by Dr. 

 Wooldridge. Half a drachm of the liquor ammonite 

 was injected by myself into the left external jugular 

 vein. 



Result. In not less than ten seconds, the heart's 

 action became more forcible and rapid. 



Ten minutes afterwards, injected the same quantity 

 into the external jugular vein. 



Result. Same effects, and none other. 



After waiting fifteen minutes, the same quantity 

 was injected into the right ventricle of the heart. 



Result. More instantaneous, but the same results 

 as before ; the dog becoming conscious, more chloro- 

 form was put into the bellows. 



Fifteen minutes afterwards, the same amount was 

 thrown into the left ventricle of the heart. 



Result. Instantaneously, the muscles of the ex- 

 tremities were extended ; respiratory efforts were 

 forcibly made. After this, he perfectly recovered. 

 But I went further, and injected into the left ventricle 

 twice the amount of the solution of ammonia, and 



