570 NERVOUS SYSTEM. 



tres. This action probably takes place through filaments which pass from 

 the fifth to the mucous membrane, through Meckel's ganglion. 



Remote Effects of Division of the Trifacial. After section of the fifth 

 nerve in the cranial cavity, the immediate loss of sensibility of the integu- 

 ment and mucous membranes of the face and head is usually supplemented 

 by serious disturbances in the nutrition of the eye, the ear and the mucous- 

 membranes of the nose and mouth. After a period varying between a few 

 hours and one or two days after the operation, the eye upon the affected side 

 becomes the seat of purulent inflammation, the cornea becomes opaque and 

 ulcerates, the humors are discharged and the organ is destroyed. Conges- 

 tion of the parts is usually very prominent a few hours after division of the 

 nerve. At the same time there is an increased discharge from the mucous 

 membranes of the nose and mouth upon the affected side, and ulcers appear 

 upon the tongue and lips. It is probable, also, that disorders in the nutrition 

 of the auditory apparatus follow the operation, although these are not so- 

 prominent. Animals affected in this way usually die in fifteen to twenty 

 days. 



In the early experiments of Magendie, it was noted that " the alterations 

 in nutrition are much less marked " when the division is effected behind the 

 ganglion of Gasser than when it is done in the ordinary way through the 

 ganglion. It is difficult enough to divide the nerve completely, within the 

 cranium, and is almost impossible to make the operation at will through or 

 behind the ganglion ; and the phenomena of inflammation are absent only 

 in exceptional and accidental instances. Magendie offered no satisfactory 

 explanation of the differences in the consecutive phenomena coincident with 

 the place of section of the nerve. The facts, however, have been repeatedly 

 verified. In a number of experiments in which the nerve was divided in the 

 cranial cavity (Flint), the consecutive inflammatory effects were almost always 

 observed ; but in an experiment made in 1868, the nerve was completely 

 divided on the left side, as was shown by total loss of sensibility of the parts 

 to which it is distributed, and the animal (a rabbit) lived nearly four months. 

 Four days after the operation the loss of sensibility was still complete. There 

 was very little redness of the conjunctiva 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 distinct but slight. 

 There was no redness of the conjunctiva, and the opacity of the cornea had 

 disappeared. The animal was in good condition, and 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, and there was no inflammation 

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

 become extremely emaciated. The animal never recovered power over the 

 muscles of the left side, and the incisors grew to a great length, interfering 

 very much with mastication. 



Longet, in 1842, gave an explanation of the absence of inflammation in 

 certain cases of division of the fifth. He attributed the consecutive inflam- 



