In the peripheral nerve-fibres no constant material changes have been observed. The epineurium, on the other hand, is almost invariably shrunken and sclerosed. Considerable stress might be laid on this fact unless it were also taken into consideration that the nerves were examined in patients who had suffered from major neuralgia for prolonged periods of time. Similar changes have also been observed in patients who have never exhibited neuralgic symptoms. In the ganglion itself the following changes have been observed:--(1) arterio-sclerosis; (2) alteration in the character of the nerve-fibres traversing the ganglion; and (3) adhesions between the ganglion and the surrounding parts. All these changes, however, are so inconstant that but little importance can be attached to them. At the present time there is a disposition to regard trigeminal neuralgia in the light of an ascending neuritis, originating peripherally and ascending towards the Gasserian ganglion. Sir Victor Horsley first pointed out that the ganglion acts as a barrier to the further upward spread of the affection. This is proved by the success obtained in the removal of the ganglion. Symptomatology. _Pain._ The onset of pain may be preceded by premonitory symptoms such as tinglings, throbbings, and burning sensations in the parts subsequently involved, whilst, in the earlier stages of the disease, the pain may be more or less localized to the site of emergence of the nerve from an osseous foramen. In the earlier stages also the attacks, though severe, are paroxysmal, of short duration, perhaps not lasting more than half a minute, and definitely localized to some special nerve-trunk. During the periods of remission the patient feels quite well. Gradually the pain increases in severity, the periods of remission shorten, and the pain in its distribution becomes more widespread, the neuritis--or whatever the process may be--spreading centrally and radiating along the course and distribution of such branches of the nerve as shall be encountered. Paroxysms are a marked feature, occasionally of so severe a nature that the patient falls to the ground as if struck by lightning, recovering after a variable period of time. In the later stages of the disease the pain may be almost continuous, and the condition of the patient is truly miserable. The attacks are often ushered in by the slightest stimulus--talking, mastication of food, draughts, emotion, &c.--and, in order to avoid the occurrence as far as possible, the patient abstains from talking, dreads eating, &c. Dribbling from the mouth may be observed in those cases in which the patient finds some relief in keeping the mouth open. It is also frequently seen during the height of the paroxysm. At such stages the patient is collapsed, with feeble pulse, shallow respiration, the temperature subnormal, and the skin clammy. The attacks occur both during the day and the night, sleep fails, and the body nutrition suffers.