account this method has been almost entirely replaced by mercury vapor lamps, either the Finsen-Reyn lamp with a quartz tube and quartz compressor, or the more simple glass mercury vapor lamp.

The quartz lamp is most useful in treating lupus, rodent ulcer, either on the surface or more deeply placed, and also by use of quartz rods on mucous membranes of nose, rectum, vagina, etc.

The ordinary mercury vapor lamps are more useful in treatment of superficial large areas of lupus, lupus erythematosus, and in many skin diseases, as chronic eczema, and are especially useful in alopecia: it seems to induce a growth of hair when all else has failed.

We now come to the method of treatment by radiant energy, which is probably the most useful of all, viz., X-ray or Röntgen rays. During my seventeen years' work I have learned to have less and less respect for some of these methods and more and more for others. Treatment by X-rays certainly is becoming more and more useful, and the range of diseases benefited by it greater in number. This is partly due to improvements in apparatus, but still more is due to improvements in technic, which is each year getting more exact as experience teaches the workers with this powerful method of treatment.

We have had electrical appliances sufficiently powerful to produce suitable currents, but the X-ray tube, although much improved, has limited our efforts. Quite recently, however, a new departure in tubes has been made in Germany and America, and in the X-ray tube of Dr. Coolidge, of America, we are promised as great a revolution as was effected in cycling and motoring by the adoption of the pneumatic tire. In an ordinary X-ray tube we use the electrons of the residual air to carry the current and produce X-rays by their impact on the anticathode of the tube, and our tubes become useless by the vacuum getting too high or two low; i.e., by there being too few or too many of these electrons.

In the Coolidge tube the air is pumped out so as to produce as perfect a vacuum as can possibly be obtained, and no electrons are left to carry any current. The cathode is made of tungsten wire, like that in metal filament lamps, in a flat spiral in a tube of molyb denum, and electrons are produced from this wire in as few or as large quantities as are wished by heating this tungsten spiral by a

battery current; the coil current then hurls them against the tungsten anticathode: this weighs four ounces.

In one test 25 milliampères were passed for 50 seconds (i.e., 1250 milliampère-seconds) without harming the tube, whereas the best of ordinary tubes will not stand more than 10 milliampères for 5 seconds, or 50 milliampère-seconds; i.e., the Coolidge tube can give at least 25 times more current, and should be able largely to replace radium in the treatment of malignant growths, etc. This, however, is for the future. What has already been done and can be done now?

X-rays have proved to be most useful in the treatment and cure of lupus, rodent ulcers, superficial epitheliomas, and superficial recurrent nodules of carcinoma. It is becoming the routine treatment, after surgical removal of epitheliomas, carcinomas, and sarcomas, to have X-rays applied to the whole area involved, to prevent recurrence, and this should be done at intervals ranging from one week to six weeks and from four to a dozen or more times. I have treated many such cases and have the greatest faith in its efficacy. One should filter the rays for this purpose.

In 1903 I wrote:

If I myself were unfortunate enough to get epithelioma, say of the lip, would I have it excised or would I X-ray it? Certainly I would X-ray it first, and, if that did not do, I should have it excised and then should X-ray the parts afterwards. The same with lupus and rodent ulcer-I should certainly X-ray them first.

If I got a carcinomatous or sarcomatous tumour I should first have it excised thoroughly, and if I survived I should X-ray the part afterwards and continue doing so from time to time, so convinced am I of its local beneficial action,

and to-day I strongly endorse this opinion.

Now what about the treatment of inoperable malignant tumors by X-rays; and, if you will allow me, I will here add, and by radium? Should we use them or advise their use or not? Well, the rule is, I believe, very simple. If we can give the deeper and less accessible spots a sufficient dose to cause degeneration of the malignant cells, then certainly use X-rays or radium; if we cannot, then as certainly do not use them. It has, I believe, been abundantly proved by many workers, and especially by Professor Abbe, of New York (see British Medical Journal of last year), and Professor Clunet, of Paris (see next April's issue of the Journal of British Röntgen Society), that both X-rays and radium have the following action, which may be easily illustrated by treatment of a malignant ulcer of the skin.

In the centre, where dosage is greatest, there is actual destruction of malignant and all other epithelial tissue; beyond this, there is retardation of growth, and beyond this, again, actual stimulation and often rapid increase of growth. If oat grains are exposed to X-rays or radium for, say, one hour, their subsequent growth is prevented; if for half an hour, the growth is retarded; if for five minutes, they grow much more strongly than ordinary oat grains.

Therefore expose the malignant growths to sufficient dosage of X-rays or radium to retard growth of its ultimate parts, or, if this is impossible, don't expose them at all.

If in one part of a body, for instance, malignant glands were so accessible, and in another part they were not, it would be quite justifiable to treat the former, but not the latter, unless, of course, the latter were certain to kill the patient before the former. One point one must also remember: X-rays often cure the pain of painful inoperable cancers in a wonderful way.

X-rays have been very extensively used during the last five years on the continent, and more recently in England, for the treatment of uterine fibroids and also for the menorrhagia of the menopause. There are two schools of treatment: (1) Those who follow Professor Albers Schonberg, of Hamburg, who has for five years used the moderate dose method; i.e., filtered doses for four days in succession, about eight minutes a day, with a fortnight's interval, and then another four days, another fortnight's interval, and so on. (2) The intensive method of Gauss, of Freiberg, who uses massive doses of several hours' duration, but uses them only once or a few times. They both use very hard X-rays, filtered through two or three millimetres of aluminum and some leather or bromide paper.

This treatment is extraordinarily successful; Albers Schonberg has had 78 per cent. cures of all cases treated during five years, and Gauss is so successful that I heard a gynæcological surgeon complain that there were now no operations for them to do in Freiberg except for appendicitis and such like.

I have not as yet done any fibroids, but there is no inherent difficulty in them. The treatment of climacteric menorrhagia not due to fibroids is easier and requires small doses only, and is very successful.

X-rays are also very successful in the treatment of splenic leukæmia, and patients tolerate much dosage; the chief drawback is

that if X-ray treatment is left off altogether the leukæmia gradually returns, but it can be kept at bay by exposures at long intervals.

X-rays have also been used in the treatment of exophthalmic goitre or Graves's disease, and I have had several fairly successful results. It is better to expose only half or two-thirds of the thyroid gland, as in cases in which the whole gland was irradiated the Graves's disease was cured and myxedema supervened. It is certainly a safer treatment than operation, in my opinion, and more useful than any other form of treatment, except very prolonged rest.

X-rays are also very useful in the treatment of painful affections, as sciatica, lumbago, troublesome neuralgic affections of posterior nerve-roots, and other forms of neuritis. Hard and filtered X-rays should, of course, be used, and are best applied to point of emergence of the respective nerves.

X-rays are very useful in the treatment of many skin complaints, especially when of a chronic nature, such as pannus, trachoma, keloid, psoriasis, and chronic eczema. One can often cure cases of dry, indurated chronic eczema that have lasted for many years.

X-ray treatment is a certain cure for hyperidrosis, especially for the excessive sweating of axillæ. It is very useful in hypertrichosis or excess of hair on ladies' faces, but a permanent, more or less shiny spot replaces the hairy area.

X-rays are most useful in the treatment and prevention of boils and in severe acne. Its proper use in chronic acne of the face, neck, and back is very gratifying to patient and doctor. For instance, two years ago I treated a young man whose back had for five years been riddled with furuncular acne, despite all sorts of treatment: about twelve applications of X-rays quite cured him, and he has had no recurrence since, and I have had many successful cases.

Last but not least, X-rays are now the method of cure of ringworm of the scalp. As I can claim this method as a child of my own, I hope you will forgive me if I tell you about it. I believe I was the first person in Great Britain to suggest and successfully use X-rays for ringworm.

My first successful case was begun in November, 1902, and finished early in January, 1903; I show you a photograph of this case, taken some months afterwards, when the hair had grown again.

This case was followed by many others, the results of which I published in the General Practitioner in 1904.

I wrote a fuller paper in November, 1904, which, with photographs, was published in the Archives of the Röntgen Rays in August, 1905. In this is shown what I believe to be the very first case in which the whole head was treated. This was done in the second half of 1903.

In December, 1906, I devised and tried an overlapping open method; that is, one which obviated the necessity of protecting devices on the child's head. I show you some photographs of the first case so treated, which was most successful.

Soon after that Dr. Agnes Savill tried the overlapping open method, and then Drs. Adamson and Critchley in this country and Dr. Kienböck in Vienna much improved the overlapping open method and invented the 5-inch, 5-area naked overlapping method, now almost invariably used. Sabouraud's pastilles and distance were adhered to, the distance being measured by transparent wooden rods, which are usually called Kienböck's, but which I prefer to call Adamson's, because I believe that he and Dr. Critchley used them first.

This method is very safe and satisfactory, but, as it entails the head being at least six inches from the anticathode, it is rather slow and tedious if many cases have to be treated.

To get over these difficulties, Dr. Hampson devised a method for shortening the time required by putting the pastille on the child's head and bringing the head to within about 41/2 inches of the anticathode that is, the "half-time distance." I have worked with his method, and find it efficient and quicker, but, in my opinion, it has two disadvantages: that it is very difficult for most workers, even in the proper artificial light, to match accurately all the requisite tints; and that without some other control it is hardly safe enough.

To overcome these disadvantages I devised a modification in technic, which I think combines the safety of the Adamson or Kienböck-Sabouraud method with the rapidity of Hampson's. I have had a wooden tube shield made with a full 5-inch aperture, and with transparent distance rods of such a length that by simply removing them with their holder and putting the child's head at the level of the aperture one moves it from the "full-time" Sabouraud distance to the "half-time" Hampson distance; for instance, with a 5-inch (or