Properties and Uses. - Local anaesthetic similar to cocaine, but dilates bloodvessels, whereas cocaine contracts them; heart tonic, but only one-half as toxic as cocaine. Dose, gr. 1/30 (.002 Gm.), in pill; locally in the eye 4 p. c. solution, on other mucous membranes (laryngology, etc.) 5-10 p. c. solutions; hypodermic injection (local anaesthesia) 1 p. c. solution.

Opsonins. Bacteria Vaccines. Opsonic Theory. - It is claimed that the blood fluids so modify bacteria germs as to render them readily devoured by the white blood-corpuscles (leukocytes, phagocytes), and the elements in the blood fluids causing this effect are called opsonins. These are supposed to act by chemically uniting with and changing the invading bacteria so that they become absorbed by the leukocytes, which are themselves neither stimulated nor otherwise affected. Opsonins in the blood plasma are of many varieties, each special in combating a particular kind of bacteria, while leukocytes of healthy and diseased persons are active alike in the same serum, so that the amount of opsonins present in the blood determines an individual's susceptibility to bacterial invasion.

For treatment must (1) isolate in pure culture the causative microorganism, (2) estimate opsonic power of patient's blood to this microorganism, (3) prepare and standardize a vaccine from this micro-organism - provided the opsonic index be at or below normal, (4) inoculate patient with proper dose and frequency of this vaccine, as shown by a systematic estimation of the opsonic content of the patient's blood.

The starting point of opsonins are 24-hour pure cultures of the peculiar disease micro-organism causing the particular disease for which the vaccine is given, the culture being removed from the surface of the media by small quantity of sterile salt solution, which holds the germs in suspension. The number of germs in salt suspension is compared with the number of red corpuscles in same quantity of human blood, the density being adjusted by the operator according to his needs in fixing the number of germs for a dose.

Uses. - Tuberculous joints, septicemia, endocarditis, Malta fever, etc. The number of micro-organisms for a dose depends upon the disease, condition of patient, and virulency of the micro-organism used in preparing the vaccine: Staphylococcus vaccine - three hundred millions; pneumococcus and streptococcus - fifty millions; Gonococcus - ten millions; Tubercle (T. R.) - 1/3000 - 1/800 of a milligram.

Roentgen Rays. x-Rays. Radio-activity. - If electric sparks be passed between the poles of a highly exhausted glass tube (Crookes') a faint, straight-lined radiation (cathode rays) emanates from the cathode, which consists of a stream of very minute, rapidly moving, negatively charged particles. These cathode rays impinge on the walls of the tube, producing a brilliant fluorescence, while at the same time a new kind of rays (Roentgen- or x-) pass out in straight lines from the walls of the tube, which are invisible, not easily deflected by a magnet, but very efficient, causing many substances to become luminescent, passing through bodies opaque to ordinary light waves, affecting photographic plates, producing physiological effects on living tissues, and changing insulating media (air, gases, paraffin, etc.) into conductors when passing through them.

Inasmuch as Crookes' tubes are fluorescent while emitting x-rays, it was thought that the latter might be given out, possibly, by various fluorescent bodies. Uranium salts, noted for their fluorescence after exposure to sunlight, were found to affect sensitive plates covered with black paper impervious to ordinary light. Becquerel, working along this line, placed some double sulphate of uranium and potassium on a covered photographic plate, but, owing to a sudden storm obscuring sunlight, thus rendering impossible the exposure of the uranium salt to the sun for the production of fluorescence, he laid away carefully in a dark drawer the plate with the uranium salt upon it. Some days afterward he happily decided to examine this same plate for possible changes, and in the development, much to his surprise, found that it had been affected greatly, thereby discovering the remarkable radiation - Becquerel rays or radio-activity. Any substance, therefore, which like uranium, emits such invisible rays, that affect a photographic plate or pass through opaque substances, is said to be 7'adio-active. Madame Curie found in uraninite (pitchblende, a complex substance, and the source of uranium salts) several elements - polonium, actinium, radium - far more radio-active than uranium and its salts.

Radium, although never yet isolated (only 1 Gm. of the salts existing at a cost of $6000), is an alkaline earth resembling barium, with a radio-activity 100,000 times stronger than that of uranium; its salts (bromide, chloride, sulphide) are white, crystalline, grayish in time, self-luminous, imparting luminosity (phosphorescence) and radio-activity to neighboring bodies temporarily, emit heat constantly, reduce silver salts and mercuric chloride, convert white to red phosphorus, and color glass, porcelain, paper, rock-salt, just as cathode rays do.

As sun rays consist of rays of light, heat, and actinic power, so radio-active bodies possess three kinds of rays: alpha (a) - having slight penetrating power (completely absorbed by a few centimeters of air or a sheet of paper), being deflected with difficulty by a magnet and consisting of a stream of particles, twice as heavy as the hydrogen atom, positively charged, moving at great velocity; it is to the bombardment of these particles that the self-heating of radium salts is believed to be due; beta (β) - having a marked power of penetration and of exciting phosphorescence in a large number of substances (barium platinocyanide, zinc sulphide, etc.), being deflected easily by magnet, similar in character to the cathode rays and consisting of streams of negatively charged "corpuscles" or "electrons," one-thousandth part of the mass of the hydrogen atom, moving at great velocity; gamma (y) - being a very penetrating kind of Roentgen rays, produced at the moment of sudden expulsion of the beta rays, and capable of penetrating a foot-thickness of iron.

Properties and Uses. - Rays of radium salts and x-rays closely resemble. Chiefly in lupus, cutaneous tuberculosis, superficial epithelioma - the radium salts being applied locally to the affected part in a small rubber bag, box, disc, or cylinder. A radium salt when even thus enclosed and brought near the temple or closed eyes causes the sensation of light, and although no portion of the body can detect its presence, yet a strong influence, similar to z-rays, is exerted upon the tissues. The skin often does not redden until weeks after the exposure, when intractable sores may result, while a small quantity sealed in a glass tube will kill fish when placed into a bowl containing them. The extreme expense and lack of uniformity of the radium salts restrict greatly their use.