VOL. LXXXV.] PHILOSOPHICAL. TKANSACTIONS. SIQ 



the 2d cervical to join the phrenic of the right side, but too insignificant to have 

 any effect on the experiment. This experiment confirms those made by Mr. 

 Hunter, in which he recovered the animals by inflating the lungs, and on which 

 his method of recovering apparently drowned people principally rests. It shows 

 that respiration is the prime mover of the machine, and it takes off whatever 

 objections might have been raised, from the animals on which he made his expe- 

 riments, having the connection with the brain entire, as the par vagum and in- 

 tercostals were not divided, since here the same thing took, place in these expe- 

 riments where nerves could have no effect. 



VII. An Experimental Inquiry concerning the Reproduction of Nerves. By 



John Haighlon, M. D. p. J QO. 



An animate machine differs from an inanimate one in nothing more conspi- 

 cuously, than in its power of repairing its injuries, and of curing its diseases. 

 It is wisely contrived by nature that, in many instances, the cause producing the 

 injury lays the foundation for the cure; for as injuries, particularly those occa- 

 sioned by cutting instruments, are necessarily attended with an effusion of blood, 

 from the division of blood-vessels, this fluid, either immediately or remotely, 

 fills up the breach. Hence every part possessed of vascularity, and consequently 

 of blood, carries with it the principle by which it repairs its injuries; and the 

 facility with which this process is conducted, generally bears some proportion to 

 the freedom of the circulation in each individual part. 



But it has been a subject of inquiry with anatomists and physiologists, to deter- 

 mine of what nature the new formed part is, and how far it may be said to pos- 

 sess the characters of the original part. There are (esN who will deny that a bone, 

 when fractured, fills up the chasm with a substance of its own kind; or that a 

 tendon, when divided, repairs with a substance resembling itself. But this law 

 of nature is not admitted as universal ; and this power of repairing in kind has 

 been denied to several of the constituent parts of an animal machine. With 

 respect to the nerves, it has been both affirmed and denied : some assert that the 

 new formed substance possesses the characters of the primitive nerve; others 

 maintain that it is totally different ; and both found their opinions on experiment. 

 When opinions so opposite to each other prevail, on a point which experiment 

 seems so fully adequate to decide, we are naturally led to take a view of the 

 manner in which the experiments were conducted, and consider the criterion to 

 which each party appealed.* 



There are only 2 tests which seem to offer themselves, and from which any 

 degree of judgment can be formed. These are, either a minute and careful ex- 

 amination of the new formed substance in an anatomical way, and an accurate 



• Vide Fontana and Amemann. — Orig. 



