528 NERVOUS SYSTEM 



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

 tions 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 com- 

 pletely, within the cranium, and is alrrfost 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 these differences in the 

 consecutive phenomena, but the facts 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 nearly 

 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 sensi- 

 bility 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 slight streak of opacity, so slight that 

 it was distinguished with some difficulty. Twelve days after the opera- 

 tion, 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 con- 

 tact 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, seriously interfering with mastication. 



The explanation of the phenomena of disordered nutrition in the 

 organs of special sense, particularly the eye, following division of the 

 fifth, is not afforded by the section of this nerve alone ; for when 

 the loss of sensibility is complete after division of the nerve behind 

 the Gasserian ganglion, these results may not follow. They are not 

 explained by deficiency in the lachrymal secretion ; for they are not 

 observed when both lachrymal glands have been extirpated. They are 

 not due simply to an enfeebled general condition ; for in the experiment 

 just detailed, the animal died of inanition, after section of the nerve, 

 without any evidences of inflammation. In view of the fact that section 

 of the sympathetic filaments is well known to modify the nutrition of 

 parts to which they are distributed, producing congestion and increase 

 in temperature, it is rational to infer that the modifications in nutrition 

 which follow section of the fifth after it receives filaments from the 



