NITRATE OF POTASH.
295
on tlic authority of J. E. M. Smith, that half an ounce applied to thethigh killed a dog in thirty-six hours. Eight ounces dissolved in a pintof water, and swallowed, killed a horse in twenty-four hours with all thesymptoms of violent intestinal irritation, (Moiroud, Pharm. Veter.) Ve-terinarians use nitre as a diuretic and refrigerant in doses of from two tofour drachms.
(c.) On man. —In very large doses (such, for example, as one ounce ormore) nitre has in several instances caused death ; but the effects of itare not uniform, since, in other cases, this quantity has not appeared tohave any very remarkable or obvious effect. For example, Dr. Christisonknew an instance in which one ounce was taken without occasioning anyother unpleasant symptom than vomiting; and it was retained on thestomach for above a quarter of an hour. In those cases where violenteffects followed the ingestion of it, the symptoms were twofold : on theone hand, those indicating inflammation of the alimentary canal (such aspain, vomiting, and purging ;) on the other hand, an affection of the ner-vous system (marked by giddiness, convulsions, failure of pulse, tendencyto fainting, dilated pupil, insensibility, and palsy.) It is probable thatthe operation of nitre is influenced by the quantity of aqueous liquid inwhich the salt was dissolved, and that the more we dilute, the less power-fully does it act as a poison. In no other way can we reconcile the dis-crepant statements in regard to the effects produced by an ounce of nitre.
If nitre (or any other neutral alkaline salt) be mixed with dark-colouredvenous blood out of the body, it communicates to it a florid or arterialhue. Now as this salt, when taken into the stomach becomes absorbed,it is not unreasonable to suppose that while mixed with the circulatingblood it might have an analogous effect. Dr. Stevens ( Observations onthe Blood, p. 298) asserts, that in the last stage of fever, when the bloodis black, it has this effect. Moreover, he tells us (p. 154) that in a casewhich occurred in America , where a person swallowed an ounce of nitre,by mistake, in place of Glauber’s salts, the blood when drawn from avein was completely florid, and remained as fluid as if the nitre had beenadded to it out of the body. (For some remarks on the effects of nitreon the blood, by Mr. Carlyon, see Med. Gaz. vol. viii. p. 626 ; and onnitre as a therapeutic agent, by Dr. Hancock, see Lancet for 1831-2,vol ii. p. 766.)
In moderate doses nitre acts as a refrigerant, diuretic, and diaphoretic.Its refrigerant properties are best seen when the body is pretematurallyhot, as in febrile disorders. Mr. Alexander ( Essays , pp. 105, et. seq.) inhis trials with it, made on himself, experienced a sensation of chillinessafter each dose, but he could not recognise by the theimometer anydiminution of heat in the external parts of his body. He found in mostof his experiments that it had a powerful influence over the vascularsystem, and surprisi ngly dimin ishe d, in a ver y short period of time, thenumber of pulsationsrA^rusT on several occasions a drachm of this salt,within a few minutes, reduced the frequency of his pulse from 70 to 60beats. Sundelin ( Heilmittell. Bd. i. S. 59) says nitre diminishes theorgasm and plasticity of the blood perhaps by a chemical action on thecruor and fibrin. Diuresis is another, and very generally observedeffect. As the nitre can be detected in the urine, its operation as adiuretic depends perhaps on the local stimulus which is communicated tothe renal vessels while the nitre is passing through them. Like most of the