DURING the last 32 years I have seen 90 cases of intractable trigeminal neuralgia, 86 of whom I have treated with alcohol injection ; 65 were females and 25 were males. In only three cases was no relief obtained, owing to the nerve not being found ; one of these had previously been operated on unsuccessfully for gasserectomy and the scar tissue was so dense that it was impossible to manipulate the needle. In three others slight definite improvement resulted and in the remaining 80 cases

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... relief was obtained for intervals varying from as little as two months and four months in two cases to 22 years and more. For the majority 12 months' complete relief of pain may be looked on as a minimum, if the nerve is definitely hit and anaesthesia produced; while two to three years and more may be expected when the depth of the anaesthesia indicates that the nerve has been properly destroyed by the alcohol. Several patients have come to me who had previously been unsuccessfully injected with alcohol elsewhere, and I have heard it stated that the treatment was of no use, and also that no anaesthesia is produced by the alcohol injection. That this may be so in the hands of those who have not practised the method thoroughly on the dead body, or who have not the patience to find the nerve before performing the injection in the living patient, I can readily believe. I wish to state most emphatically that such failures in cases of genuine trigeminal neuralgia are due to errors in technique, owing to which the nerve is neither struck nor injected with the drug. Strong alcohol injected into any nerve trunk destroys the nerve fibres almost instantaneously ; it is, indeed, a chemical resection of the nerve, and total loss of function of the nerve will ensue until regeneration occurs. It is to prevent this regeneration of nerve fibres that I have adopted the modified technique described below, in order to destroy the nerve cells in the Gasserian ganglion, and thus to render impossible the downgrowth of new nerve fibrils to replace those destroyed by the alcohol. The great advantage of extirpation of the Gasserian ganglion over Schlosser's method of alcohol injection of the nerve trunks has been the permanence of the cure in the former treatment, as opposed to the temporary relief of a few months to three or more years obtainable by the injection. The severity of the Krause-Hartley operation for extirpation of the Gasserian ganglion, owing to the necessity for a large trephine opening, and considerable pressure being exerted upon the brain during the process of exposing the ganglion, has deterred a large number of sufferers with trigeminal neuralgia from seeking relief by this means. I have therefore endeavoured to improve on the method of deep alcohol injection of the nerve trunks by carrying the injection of strong alcohol through the foramen ovale into the Gasserian ganglion itself, in order that, by destroying the nerve cells in the ganglion, regeneration of nerve fibres along the degenerated nerve trunks shall be prevented, and thus to substitute permanent cure of the pain for the temporary relief of a few months to a few years which was hitherto obtainable. In this way it appears to me possible to obtain all the advantages of the Krause-Hartley operation without its attendant deformity and dangers, or even the necessity of a general anaesthetic. In my first paper 1 three years ago on the alcohol injection treatment, I indicated that in practically every case it is possible to pass the needle through the foramen ovale into the Gasserian ganglion, and I had found'by experiment on a large number of bodies in the post-mortem room that it was possible to inject the Gasserian ganglion through this foramen, using an alcoholic solution of methylene blue for the purpose, the ganglion being found afterwards stained deeply blue with the dye. I then felt that partial or complete destruction of the ganglion by injection of alcohol into it through the foramen ovale would be the ideal treatment in 1 those cases of neuralgia which involve the third division of the nerve either alone or in conjunction with the second division, which form a majority of the total number of cases of trigeminal neuralgia met with. No recurrence of the pain after such a treatment should ever happen, just as in cases when the Gasserian ganglion has been successfully extirpated. It is a debatable question whether in those cases of neuralgia limited to the first and second divisions it is better to practise recurrent injections for the two nerve trunks and leave the important area of sensation on the tongue and lower jaw supplied by the third division unimpaired, or whether it would be better in every case to attack the ganglion through the foramen ovale, and thus render the whole area of the trigeminal nerve anaesthetic. That is to say, is it better to suffer the return of the neuralgia at intervals with recurring injection treatment and retain sensation on the tongue and lower jaw, or is it wiser to purchase permanent immunity from pain at the price of permanent loss of sensation on the half of the tongue and lower jaw, in addition to the numbness over the area of the trunks affected by the neuralgia ? During the last 15 months I have injected the ganglion through the foramen ovale with 90 per cent. alcohol in seven patients, one man and six women. At first I attempted this only in thin subjects who had not been injected before, because of the greater ease of manipulation of direction of the needle, and in patients in whom the third division was chiefly involved, but I have now also used it for cases in which the second division alone was affected, and I am inclined to think it will be the sounder course to use the method also in those comparatively uncommon cases in which the paroxysmal neuralgia is limited to the first and second divisions of the nerve. True trigeminal neuralgia affecting the first division alone is very rare ; I have had only one case in 90 cases of the disease. Destruction of the nerve trunks outside the skull, in cases of trigeminal neuralgia-whether by the knife or alcohol injection-is probably always followed, sooner or later, by recurrence of the pain, the intervals of freedom varying from a few months to three or four years, according to the degree to which the nerve has been destroyed. It is true that in many instances injection of alcohol in the neighbourhood of the nerve trunk has been followed by complete relief of the pain for a few weeks or months, even when no trace of anesthesia has been produced ; such perineuritic injections are, however, most unreliable in their effects, as the pain may recur at any moment. To ensure complete freedom from pain for many months it is necessary to inject the alcohol into the nerve trunk, so that lasting anassthesia shall be produced. The success of the injection can be accurately gauged by the depth of the ansesthesia produced, and if this be done properly, so that there is complete loss of sensation to touch, pin-prick, and to pressure over the larger portion of the area supplied by the nerve, we may then count with tolerable certainty on complete relief of the pain lasting from twelve months to two or three years. I have, indeed, several patients who have had no return of pain whatever for the last two and a half years. Extremely satisfactory though these results are, as the injection can be repeated if the pain returns, yet it is obviously preferable to obtain permanent relief, without having recourse to renewed injections at intervals.