518 PHILOSOPHICAL TKANSACTIONS. [aNNO 1795. 



Exper. 8. By detaching the scapulae of a dog from the spine, and partly from 

 the ribs, I got at the axillary plexus of nerves, on both sides, from behind. I 

 separated the arteries and veins from the nerves, and passed a ligature under the 

 nerves, close to the spine. I thought I could discern the phrenic nerves, and 

 instantly divided 2 considerable nerves going off from each plexus. The action 

 of the diaphragm seemed to cease, and the abdominal muscles became fixed, as 

 if they had been arrested in expiration, the belly appearing contracted. His res- 

 pirations were now about 25 in a minute, the pulse beating 120. As I was not 

 willing to trust the experiment to the possibility of having divided only one of 

 the phrenics, which I afterwards found was really the case, and some difFerent 

 nerve instead of the other, after carefully attending to the present symptoms, I 

 divided all the nerves of the axillary plexus, of each side. The ribs were now 

 more elevated in inspiration than before; respirations were increased to 40 in a 

 minute; the pulse still beating 120 in the same time. Finding that respiration 

 went on very easily without the diaphragm, in about -j- of an hour after dividing 

 the axillary plexus of each side, I divided the spinal marrow, as in exper. 6. 

 The whole animal took the alarm, all the flexor muscles of the body seemed to 

 contract, and instantly to relax again ; he died as suddenly, as if the spinal mar- 

 row had been divided in the upper part of the neck. I then opened the chest, 

 and found the heart had ceased its motion; I immediately introduced a large 

 blow-pipe into the trachea, below the cricoid cartilage, and inflating the lungs, 

 imitated respiration. The heart began to move again, and in about 3 minutes 

 was beating 70 in a minute. I recollected that there was still a communication 

 between the brain and the thoracic and abdominal viscera, that the par vagum 

 and intercostals were entire, and turning to the carotids, divided the nerves. I 

 then went on inflating the lungs as before; the heart, which had stopped, began 

 to move again, beat 70 in a minute, and continued so for near -l an hour after 

 the animal had seemingly expired. These appearances were not confined to the 

 neighbourhood of the heart; one of the gentlemen who assisted me, cried out 

 once, that he felt the pulse in the groin. I now ceased to inflate the lungs, and 

 presuming that I could easily reproduce the heart's action, allowed 3 minutes to 

 elapse. On returning to inflate the lungs, I found the heart had now lost all 

 power of moving ; and that irritating the external surface with the point of a 

 knife, did not produce the smallest vibration. I then irritated the phrenic nerves 

 with the point of a knife; the diaphragm contracted strongly as often as the 

 nerves were irritated. I irritated the stomach and intestines, which also renewed 

 their peristaltic motions. I then irritated the par vagum and intercostals, about 

 an inch above the lower cervical ganglion of the intercostal; the oesophagus con- 

 tracted strongly through its whole length, but the heart continued perfectly mo- 

 tionless. On dissection, I found a small branch of a nerve, running down from 



