198 NERVOUS SYSTEM. 



February 6, 1868, the fifth pair of nerves was divided 

 upon the left side in a full-grown rabbit in the ordinary way, 

 before the class at the Bcllevue Hospital Medical College. 

 There followed instant and complete loss of sensibility on 

 the left side of the face. Four days after, the animal having 

 been fed ad libitum with cabbage, the loss of sensibility was 

 still complete. There was very little redness of the conjunc- 

 tiva of the left eye, and a very slight streak of opacity, so 

 slight that it was distinguished with difficulty. Twelve days 

 after the operation, the sensibility of the left eye was dis- 

 tinct, but slight. 1 There was 110 redness of the conjunctiva, 

 and the opacity of the cornea had disappeared. The animal 

 was in good condition, the line of contact of the upper with 

 the lower incisors, when the jaws were closed, was very 

 oblique. The animal was kept alive by careful feeding with 

 bread and milk for one hundred and seven days after the 

 operation, there never being any inflammation of the organs 

 of special sense. It died at that time of inanition, having 

 become very much emaciated. The animal never recovered 

 power over the muscles of mastication of the left side, and 

 the ineisors grew to a great length, interfering very much 

 with mastication, which seemed to be the cause of death. 



Longet, in 1842, furnished a satisfactory explanation of 

 the absence of inflammation in certain cases of division of 

 the fifth. He attributed the consecutive inflammation in 

 most experiments to lesion of the ganglion of Gasser and 

 of the sympathetic connections, which are very numerous at 

 this point. These sympathetic filaments are avoided when 

 the section is made behind the ganglion. 2 



The explanation of the phenomena of disordered nutri- 

 tion in the organs of special sense, particularly the eye, fol- 

 io wing division of the fifth, is not afforded by the section of 

 this nerve alone ; for, as we have seen, when the loss of sen- 



1 We have observed in other experiments gradual return of sensibility, after 

 what appeared to have been complete division of the fifth. 



2 LONGET, Anatomic el physiologic du systeme nerveux, Paris, 1842, tome ii., 

 p. 162. 



