6l6 PHILOSOPHICAL TKANSACTIONS, [aNNO 1795. 



perfectly united; but the quantity of extravasated blood having been less, the 

 regenerated nerves were sinaller than the original ; I observed too, that they did 

 not seem fibrous like original nerves, but the recollection that the callus of bone 

 is dissimilar to the original bone, quieted whatever doubts could arise from this 

 circumstance. The tonsils were considerably inflamed, and this circumstance 

 alone might be sufficient to account for the increased secretion of the saliva, an 

 attendant symptom of most sore throats; though I have also seen an increase of 

 viscid saliva, in the human species, from hypochondriac affections of the diges- 

 tive powers, and also from the causes of temporary debility. The regeneration 

 of the nerves which took place in the first dog, and which I think fully proved 

 l)y this experiment, was a circumstance to me then unexpected, and un- 

 thought of. 



Exper. 6. April IQth, I divided the spinal marrow of a dog, between the last 

 vertebra of the neck and first of the back. The muscles of the trunk of the 

 body, but particularly those of the hind legs, appeared instantly relaxed; the 

 legs continued supple, like those of an animal killed by electricity. The heart, 

 on performing the operation, ceased for a stroke or 2, then went on slow and 

 full, and in about a J- of an hour after, the pulse was j60 in a minute. Respi- 

 ration was performed by means of the diaphragm only, which acted very strongly 

 for some hours. The operation was performed about a J- of an hour before 12 

 at noon; about 4 in the afternoon the pulse was QO only in a minute, and the 

 heat of the body exceedingly abated, the diaphragm acting strongly, but irre- 

 gularly. About 7 in the evening, the pulse was not above 20 in a minute, the 

 diaphragm acting strongly, but in repeated jerks. Between 12 at night and 1 

 in the morning, the dog was still alive; respiration was very slow, but the dia- 

 phragm still acted with considerable force. Early in the morning he was found 

 dead. This operation I performed from tlie suggestion of Mr. Hunter: he had 

 observed in the human subject, that when the neck was broken at the lower part, 

 in which cases the spinal marrow is torn through, the patient lived for some 

 days, breathing by the diaphragm. This experiment showed, that dividing the 

 spinal marrow at this place on the neck, if below the origin of the phrenic 

 nerves, would not, for many hours after, destroy the animal ; it was preparatory 

 to the following experiment. 



Exper. 7. April 26th, I divided all the nerves of the first class, in a dog. 

 The principal symptoms of experiment 3 took place. Soon after, I performed 

 on the same animal the operation of experiment 6; the symptoms peculiar to 

 this operation also took place, while those peculiar to experiment 3 disappeared. 

 His respirations were 5 in a minute, and more regular than in experiment 3 ; 

 the pulse beat 80 in a minute. Five minutes at"tcr, I found tiie pulse 120 in a 

 minute, respiration unaltered; at the end of 10 minutes the pulse had again 



