Let X equal Unit increase of cardiac force.

Let Y equal Unit decrease of resistance.

Then the immediate effects of high frequency currents are: x plus y equals change of blood pressure o; change of pulse

rate p.

2x plus y equals change of blood pressure +; change of pulse

rate-or o.

x plus 2y equals change of blood pressure -; change of pulse

rate or o.

According to tone of cardiac innervation.

PHOTOTHERAPY.

EDITED BY MARGARET A. CLEAVES, M. D.

Radium and Its Medical Uses. By George H. Graham, M. D., Archives of the Roentgen Ray, July, 1907.

The following abstract is of a paper delivered at the Medical Graduates' College and Polyclinic on March 5, 1907. The writer pays tribute to the "brilliant researches of Mme. and the late M. Curie, following the discovery of the radio-activity of uranium by Becquerel in 1896, by which we have been placed in possession of a new element-radium of surpassing interest to the physicist from the many complex and surprising phenomena it exhibits, and to us as medical men as a therapeutic agent of the greatest value.

"Radium is one of the class of substances that are radioactive, so-called from the power they possess of spontaneously emitting radiations capable of penetrating plates of metal and other objects opaque to ordinary light. These radiations have the further characteristic properties of (1) acting on a photographic plate, (2) discharging electrified bodies of ionization, and (3) causing certain substances to fluoresce. It was this power of radio-activity which led to the discovery of radium by Mme. Curie."

He calls attention to the process by which radium is obtained from pitchblende by an elaborate and expensive process. Though pitchblende is present in many parts of the world, that "coming from Johanngeorgenstadt, in Saxony, or Joachimsthal, in Bohemia, contains the largest percentage of radium, from which it is only possible to extract a few milligrammes of a pure salt from two tons."

"When a salt of radium is first prepared, it has only about one-quarter the radio-active value it ultimately attains. The maximum value is reached in about three to four weeks, and is then constant.

"Pure radium salts are at first colorless." If, however, not entirely freed from barium, it quickly acquires a yellow or orange color. In the Bunsen flame it burns with a beautiful carmine color indicating its purity. A green color within the flame indicates that it has not been freed from the barium.

Certain peculiarities of radium have been demonstrated by Mme. Curie and others. The atomic weight is 225. It maintains generally 3° to 5° above surrounding temperature, "the heat evolved amounting to 100 calories per gram per hoursufficient to raise a weight of water equal to that of the radium from the freezing point to the boiling point every hour."

The period of average life of the radium is nearly 2000 years. It is "estimated that one-thousand-millionth part, or I milligramme of radium."

"Radium gives off three kinds of rays and a gas spoken of as an emanation. The rays are distinguished as Alpha, Beta, and Gamma rays, and are respectively characterized as being easily absorbed, penetrating, and very penetrating.

"The Alpha rays have a mass of 1.6, hydrogen being 1. They may be compared to the canal rays of Goldstein, and are positively charged particles, traveling at the speed of 20,000 miles per second. To Professor J. J. Thomson, of Cambridge, is due the credit of demonstrating this positive charge.

"The Beta rays are more deviable, and in a magnetic field of the above intensity would probably describe a circle having a radius of only 1-10 millimeter. They are analogous in all respects save that of speed with the cathode rays in an x-ray tube, the rays having a mass one thousand times less than that of hydrogen. They are negatively charged particles, moving with a speed varying from 0.2 to 0.96 of the velocity of light, traveling much more rapidly than the cathode rays, and thus being able to penetrate much greater thicknesses of matter before they are absorbed. Owing to their larger mass, the a rays have an immensely greater ionizing action than the particles, but the a rays are so quickly absorbed by the air that their action ceases abruptly at a distance of 7 centimeters

from the surface of the radium.

"The Gamma rays are believed to be electro-magnetic pulses or waves, similar to, but far more penetrating than x-ray, proceeding from a high vacuum tube. Their ionizing action is small when compared with that of the rays. On the other hand, while the a rays have little action on a photographic plate, the and y rays have a very powerful one. No deviation of the y rays takes place in a magnetic field. These penetrating y rays give rise to secondary rays, having an intense action on a photographic plate, thus causing radium radiographs to lack the sharpness of outline of an x-ray skiagram. The absorption of all three types of rays is approximately proportional to the density of the substances traversed.

"The emanation of radium is a radio-active heavy gas, which is given off when radium is heated or dissolved in water. The volume of pure emanation emitted from radium is infinitesimal. Strutt estimates that 50 milligrammes of radium would give a volume of emanation at any one time not exceeding a large pin's head. It is an extremely active gas in consequence of its radio-activity and its great diffusibility. Experiments point to the emanation being about ninety times as dense as hydrogen, or more than six times as dense as air. It has all the peculiarities of radium in respect to ionization and photographic action, but emits only a rays. It can be condensed by cooling in liquid air. It has its uses in therapeutics, as I shall presently show, but its activity is transitory, decaying to half value in 3.7 days. It has the power of exciting radio-activity in bodies in its proximity, this "induced" activity in bodies being due to invisible and unweighable deposit of radio-active matter on the surface of these bodies. The "induced" radio-activity, which emits chiefly the and y rays with a few a rays, comes down to half value in twenty-eight minutes, and is lost altogether in a few hours.

"One of the peculiar properties possessed by radium is that of exciting fluorescence and phosphorescence in various bodies, such as zinc sulphide, barium platinocyanide, diamonds, willemite (green), kunzite (red), spartaite (orange). Rubies and sapphires do not fluoresce under radium. Diamonds, after prolonged exposure, become affected throughout their whole mass chiefly by the more penetrating B and y rays, and they undergo a change of color, becoming strongly radio-active, and remaining so even for thirty-five days, notwithstanding prolonged and intense heating.

"The chemical actions of the a and B rays are many and varied. Oxygen is changed into ozone by the energy of the radiations, and white phosphorus is changed into the red variety. Mercury is said to be changed into the yellow oxide. I have converted the perchloride of mercury into calomel. A solution of iodoform in chloroform is turned purple after an exposure of a few minutes on account of the liberation of iodine by the rays.

"Hardy made some experiments on the action of radium on globulin coagulation. Two solutions of globulin from ox serum, one made electro-positive by the addition of acetic acid, and the other electro-negative by adding ammonia, were exposed to the action of radium. A drop of the positive solution became clearer, showing more complete solution, whereas the negative drop rapidly became jelly and opaque, this action being due to the rays alone. A singular change takes place in glass and quartz vessels containing radium, depending upon the degree of activity of the radium. Glass, even when free from lead, changes color from violet through yellow to black.

"After such an application nothing visible occurs until after the eighth to fourteenth day, when a small red blush is noticed, which quickly gets deeper in color. In some cases, as in fair, clear skins, and particularly if there has been any previous treatment, such as an application of ultra violet light, the reaction may commence as early as the third day; on the other hand, if there is any obstruction to the rays reaching the skin, the reaction may be long delayed. In July last I carried an ebonite box containing five milligrammes of radium in my trousers pocket in a purse with about an inch in thickness of various coins between it and my skin. After using it I replaced it in my purse and forgot it until the third day, when I removed it. Nearly six weeks afterwards I developed a small red irritable spot on the thigh, the mark of which is still very evident."

"On the physiological action of radium, omitting for the moment that on cell life and the skin, to which I shall allude later, several remarkable observations have been made. M. Danysz, in studying its action on the nervous system, irradiated the spinal column of mice, causing death in acute nervous disturbance in from three to eight days. The young mice died sooner, showing injection of the spinal cord and meninges, and abundant meningeal hemorrhages. In a dog that had been trephined the application of radium to the brain substance caused hemiplegia after a few hours.

"Its action on the virus of rabies is specially notable. Tizzoni and Bongiovanni have shown that after radium irradiation the spinal cord of an animal that died of rabies will not inoculate other animals, but will act as a vaccine. Further, an animal inoculated with rabies and showing symptoms of the disease may be cured by a prolonged radium radiation of the cerebro-spinal avia. Sirnov, who has confined these experiments, states that the action is due to the a and B rays. the other hand, other observers, as Castellane, Ivo Novi, and Danysz, have not been able to produce all the results claimed by the Italians. Phisalix, in experimenting with different venoms, found that snake poisons of an albuninoid nature lose their toxicity under the influence of the radiations or the emanations, but that alkaloid venoms, such as that of the salamander, are not affected.

On

"When buying a speciment of radium you may be told that it has an activity of 1,000,000, or 1,800,000, which means that the salt is that number of times more active than a similar weight of uranium which is taken as unity. The activity is measured by electrical methods, depending on the ionization of the air.

"For therapeutic purposes radium is usually enclosed either in a small capsule of thin glass, or in a little ebonite box with a metal cover, having a mica window in the center. The glass

capsules are liable to explode violently with the passage of an electric spark from the accumulation of a positive charge. This may be prevented by fusing a platinum wire into the glass. After such an explosion Piffard localized the lost radium in the carpet where it had fallen, by its action on a photographic plate. He then cut out the piece of carpet and sent it to a laboratory, where a good part of the radium was recovered.

"The emanation of radium may be made use of in various ways, either in its natural state, or by the induced or imparted activity of other substances, as water, cotton, wool, gelatine, bismuth, or vaseline.

"It is essential to distinguish between the potential activity of a given specimen of radium and its efficacious activity. For instance, if we take 5 milligrammes of radium bromide, having an activity of 1,000,000 uranies, the 'potential' activity for that weight of 5 milligrammes will be 5000 times that of a gramme of uranium, while its 'effective' activity, if inclosed in a capsule of aluminum, one-tenth meter thick, would be only 500 times that of a gramme of uranium. It is evident, therefore, that the essence of the therapeutic dosage of radium is time, or the duration of exposures to the rays."

"It is a problem of the highest interest, but as yet unsolved, as to what is taking place in the tissues during the latent period. The same latency occurs in the reaction following prolonged x-ray exposure. It is held by many that the first action is a constrictive one on the capillaries and small blood vessels.

. . The secondary action, or reaction, is an inflammatory one, with stimulation of cell activity and phagocytosis, accompanied by the usual phenomena of redness, heat, swelling, and irritability, rather than pain. A fine vesication occurs early in the reaction, forming later on, a thin crust, which soon peels off. The acute reaction subsides in a few days, or it may last from seven to ten days. If the reaction has been slight, only some redness and pigmentation remain, which disappear gradually; occasionally, however, taking some months to do so completely. Should the exposure have been prolonged, the whole skin may be destroyed and slough, leaving an ulcer, which, as in the case of a severe x-ray burn, may give much trouble to heal.

"The rays of radium are destructive to all cells, but primarily so to young, newly-formed, and forming cells, such as are found in inflammatory and morbid tissues. It is fortunate that this is so, as the whole of a diseased area may be cleared up without leaving the slightest sign of scarring in the healthy tissues."

In deep-seated cancer radium has not had the success it was hoped and anticipated, although Wickman has shown that the pathological tissue of cancer absorbs the rays most energeti