method led him to recommend it very emphatically for further trials in cases of similar affections. "The explanation for the action of this salt in ulcerated cancerous tumors, was supposed to be due partly to the fact that a portion of its oxygen was transmitted to the tissues, thus producing a fatty degeneration of the cancer cells (Mancini), etc.; and partly that it acted as an astringent, and so through its diminution of the onward flow of the blood produced a reunion of the wound" (Dr. Franz Brenner, Wein Med. Wochenschrift). In diphtheria it was used and highly recommended by Sachse, in Virchow's Archiv, 51. Bd., and Seeligmüller (Jahrbuch für Kinderheilkunde, 1877) as a direct specific in this affection. In this country the use of this important remedy has received but little attention in the way of reported success from its use excepting from a few observers. Among the few, however, who have tried and proved its efficacy are Dr. Thomas Drysdale, who reported— in a paper read before the Philadelphia County Medical Society, January, 1877-remarkable results from its use in diphtheria and pseudo-membranous croup. In 1880, in a paper read before this Section in New York, I also reported marked and decided success from its internal use in scrofulous skin diseases. Later, Dr. M. Landesberg communicated in The Medical Bulletin, May, 1881, very gratifying results from its topical application in epithelioma of the eyelids. Various other communications upon the efficacy of chlorate of potassium have appeared in the medical press of this country from time to time, showing the same good results from its use in America as was had in Europe. Such, in a few words, is the brief notice of the introduction and use of the chlorate of potassium.

I shall next pass to a consideration of the properties and tests of the chlorate of potassium, after which I shall give its physiological action, and its therapeutic use.

PROPERTIES.

Chlorate of potassium crystallizes in colorless, shining, rhomboidal plates, and has a cooling saline taste. It is permanent in the air, melts with decomposition at 334° C. (633° F.), gives off oxygen at 355° C. (671° F.), at the same time it forms potassium perchlorate, and at a higher temperature parts with all of its oxygen (39 per cent. of its weight), leaving potassium chloride. It requires at 15° C. (59° F.) nearly 17 parts of

water for solution; at 35° C. (95° F.) a little over 8 parts; and, at the temperature of boiling water, somewhat less than 2 parts. It is slightly soluble in ordinary alcohol, but is insoluble in absolute alcohol. It never should be triturated with sulphur, sugar, tannin, or other readily oxidizable substances, except in the presence of water; or if dry mixtures are to be made, the ingredients should be powdered separately, and mixed by means of a sieve, and without friction, in order to avoid violent explosions. As ordinarily met with in commerce, the salt contains traces of calcium chloride, from which it is freed by dissolving it in two or three times its weight of distilled water, and stirring the solution while cooling; it will then be obtained in small crystals, which, after draining and washing with cold water, are pure. When strong sulphuric acid is added to chlorate of potassium, perchloric oxyd, Cl2 04, is formed; this is a yellow, heavy gas, which, in the presence of combustible matter, or by a slight elevation of temperature, is decomposed with a powerful explosion into oxygen and chlorine. (Stillé and Maisch's Dispensatory.)

TESTS.

The aqueous solution of chlorate of potassium should not be precipitated by chloride of barium (sulphate), nitrate of silver (chloride), or oxalate of ammonium (calcium salt). After heating the salt to redness, until gases cease to be evolved, the residue should have a neutral reaction on test paper, and should not produce a red precipitate with corrosive sublimate (absence of nitrate). (Stillé and Maisch's Dispensatory.)

PHYSIOLOGICAL ACTION.

The use of this salt is said by some to be largely due to the great amount of oxygen which it contains, and therefore it is looked upon as the most potent agent in the treatment and cure of all maladies dependent on suboxidation or defective nutrition, secretion, excretion, aëration, and molecular metamorphosis. "The elements of which this salt is mainly composed, viz., oxygen and potassium, are indispensable to the genesis of healthy arterial blood, and to the recuperation of its nutritive powers, when, after making the circuit of the system, it returns to the heart as venous blood, of darkened color, and impaired coagulability" (Alex. Harkin, M. D.). No sensible

effects are produced by it in daily doses of from fifteen to sixty grains; but in doses from one to four or five drachms it renders the venous blood everywhere more florid, so that the gums. and fauces are of a bright red color, and the teeth are whitened. The appetite is increased, and in children sometimes the bowels become loose, with greenish stools. It increases the

flow of urine, and may be recovered from that secretion: sometimes it causes aching in the kidneys. It also passes off with the saliva, the bile, the milk, tears, nasal mucus, and perspiration. Isambert, in his monograph on Potassium Chlorate (Paris, 1856), showed that it was eliminated again, unchanged by the urine, saliva, tears, perspiration; and he calculates that at least 95 per cent. of the administered potassium chlorate is eliminated in the shortest space of time. He also found that it acted on the blood, serum, and tissues in precisely the same manner as water on a solution of sodium chloride. The fact that chlorate of potassium can be obtained unaltered from the secretions is no evidence that the salt cannot yield up the element of oxygen to the blood, as a part of the salt left in the system may yield up its oxygen, and the residue pass unaltered out through the secretions. How and in what manner it acts, however, is only a surmise upon my part as well as upon that of other observers. I only know its effects upon a large class of affections, and I judge its efficacy from the results arrived at in treating those diseases. The part remaining in the system, it is supposed by Dr. Alex. Harkin (borrowing the language of Bence Jones as applied to a soluble salt of iron), " diffuses into the liquor sanguinia, into every texture, into the blood globules and white blood corpuscles, making a greater formation of hæmato-crystalline, and thereby promoting that combination with protagon on which the formation of new blood globules depends."

And further: "By dyalysis all crystalloid medicines act as directly on the textures as on the blood; they act according to their chemical power when they enter the textures, and according to the chemical and physical properties of which the different textures are composed." The remainder is supposed to part with three equivalents of oxygen in the blood, leaving as a residuum chloride of potassium, which is found in the urine as well as the blood, of which it is a normal constituent. The probability of the theory of direct absorption of these equiva

lents of oxygen is strengthened by observations, which show that the constitutional changes induced by the persevering use of chlorate of potassium are similar to those ascribed by Beddoes, Hill, Thornton, and other writers, to the direct inhalation of oxygen gas; namely, an improvement of color and increase of vital and nervous energy and physical power, and more healthy performance of all nutritive and secretory functions of animal life. Isambert, in studying the action of this salt, noticed, when given in large doses, an increased diuresis, and after 20 grammes heaviness and pain in the region of the kidneys, yet no further disturbance. There were other symptoms observed, however, besides the disadvantages mentioned by Edlefsen, and further dangerous actions of potassium chlorate recognized, such as loss of appetite, gastric oppression (Isambert, 1856), salivation, strangury (burchi), sensation of dryness, slight pain in the œsophagus; in isolated cases of diarrhoea, bearing down, dull pains in the region of the loins, particularly with the larger doses. About the changes taking place in the urine, Isambert writes (after referring to Schmidt's Jahresbücher, Bd. 911): "During the whole period of elimination the urine was strongly acid, and deposited more uric acid, urates, and phosphates than during the normal condition." In excessive doses chlorate of potassium is poisonous; and Isambert relates a case with rather incomplete history, by Lacombe, in which an adult took, instead of magnesium sulphate, sixty grammes of potassium chlorate, and died in convulsions. Lacombe (1855) supposed that the profuse purgation was the cause of death. Isambert is, however, in doubt as to its effects in this respect. Ferris relates (1873): "An Irishman, of 26 years, took a tablespoonful of potassium chlorate, by mistake, instead of Epsom salts, becoming deeply cyanosed, with absence of pulse, and death." Seeligmüller relates two cases which have ended fatally by large administrations of potassium chlorate. Dr. Fountain took 29.232 grammes (after another version 40 grammes), at once, by mistake, and died. (Wiener Allg. Med. Zeitung, 1878, No. 53.)

Isambert, after performing experiments upon animals, remarks "that 30 grms. seemed to agree well with dogs, but 50-60 grms. caused death when introduced into the intestines." The action of chlorate of potassium has also been carefully summarized by Guttmann, who made the following deductions: "1. The potassium salts are all alike poisonous. 2. Adminis

tered internally they act fatally only after a few hours, and only in larger doses (though the quantity is not given), but under similar conditions, as when subcutaneously injected. 3. They diminish the frequency and energy of cardiac action, and, frequently repeated, have a cumulative action. 4. Death results from a rapid failure of cardiac action, and by epileptiform convulsions due to cerebral anæmia. Further: Blood corpuscles and muscle fibres show no change under the microscope in potassium poisoning." Buchheim, referring to the action of this salt, asserts that certainly potassium chlorate acts similarly to nitrate of potassium, which, if taken in larger quantities, may produce not only irritation of the mucous membrane, but also an inflammation of the bladder and hæmaturia. The further action and effect of this salt recently received discussion before the Philadelphia County Medical Society, in which one of the members declared that "after absorption of the potassium chlorate, the danger of blocking the kidneys mechanically with crystals of the salt, precipitated from concentrated urine, should not be forgotten." The above statement was contrary to my own experience, as I had never observed any dangerous action in this manner upon the kidneys themselves from the use of this salt in large doses. Nevertheless, I accepted the theory advanced, and at once went to work to again investigate the observation that was made, and found that the salt cannot under any circumstance have any mechanical action upon the kidneys for the following reasons: The fact, that crystals of the salt can be detected in the kidneys of those under its influence, after death, is no reason for the inference that they had acted in a mechanical way in those organs. The collection of crystals in these organs, as well as in other tissues of the body of those who have been taking large quantities of this salt, is a postmortem appearance, and is due to the change of the temperature of the body after death, which will cause the salt held in solution to be thrown down in crystals. The same result will be observed if the salt is dissolved in plain water at the temperature of the body, and on cooling below that point the crystals will be freely deposited. That well-known authority, Ludwig, with all his experience, has not observed the condition just referred to.

The views of the action of the chlorate of potassium on the economy, by this eminent teacher and others, is aptly expressed