But it is necessary to treat more particularly of a mode of using it in acute rheumatism, which, though employed by Dr. Brocklesby, of England, in the middle of the last century, was not generally adopted, and seemed to have been forgotten, until revived in 1833, in France, by MM. Gendrin and Martin Solon, whose example has been followed by other practitioners with considerable success. This method consists in administering the medicine in large doses, dissolved in a very large proportion of water, or some demulcent or slightly nutritive fluid, as barley-water, sweetened water, thin gruel, lemonade, etc. Half an ounce is given, in divided doses, during the first period of twenty-four hours, and gradually increased to six, eight, or even twelve drachms, in the same period of time. The mean quantity administered daily is about ah ounce. The proportion of liquid employed is three quarts to an ounce of the salt; so that four fluidounces of the solution, containing twenty grains, may be given at such intervals as to amount to the required quantity in the day. The quantity of liquid may be somewhat diminished when found to oppress the stomach; but the operation should be carefully watched, and the remedy suspended upon the occurrence of any disagreeable effects. it must be borne in mind that the large dilution is necessary to avoid poisonous results. in general copious diaphoresis is produced, when the patient is confined to bed and well covered. Sometimes, however, the remedy operates as a cathartic, and sometimes as a diuretic. The mean length of time required for the cure of the disease is stated at eight days. The remedy is said to be very generally successful: but it sometimes fails.

To chronic rheumatism it was supposed not to be adapted; but the experience of Dr. John Cargill would lead to a different conclusion. Of one hundred cases treated with nitrate of potassa, sixty-one were cured, and the average length of treatment was about two weeks. Of the remaining cases, twenty experienced great relief, five were but slightly benefited, three were in no degree benefited, three became worse, and of the result in eight nothing positive could be stated. At the beginning of the treatment, forty grains were given dissolved in barley-water three times a day; and this quantity was sometimes continued throughout the case; but generally the dose was increased to sixty, ninety, or one hundred and twenty grains, given at the same intervals, or every four hours. Not less than eight fluidounces of liquid were given with each dose. if accidentally administered with but little water, the medicine occasioned intense griping pain, with anxiety, depressed circulation, etc. in some rare instances, in persons of nervous temperament, general tremors, great muscular weakness, giddiness, etc. were produced; but the symptoms subsided in a few hours with diuresis or perspiration. I have been thus particular in this account, as, if the experience of others should be found to coincide with that of Dr. Cargill, the remedy will certainly rank among the most effectual in chronic rheumatism; and, in order that it may be fairly tried, the circumstances under which it proved successful should be stated. The duration of the cases before treatment had often been long, varying generally from two months to five or six years. (Lond. Med. Gaz., Oct. 1851, p. 640.)

From its supposed aplastic properties, nitre, used in the same method, might be tried in pseudomembranous croup; the dose being of course accommodated to the age of the patient.

2. Active Hemorrhages. it is only for its sedative action on the heart that nitre is indicated in the active hemorrhages; and its use has been chiefly confined to haemoptysis. So far as it has aplastic properties, it is contraindicated in these cases; and, in all hemorrhages attended with a deficiency of healthy fibrin, it could probably do only mischief; the prompt and efficient coagulability of the blood being the condition most favourable to the arresting of the discharge.

3. Fevers. it is only in the sthenic cases of fever, with an energetic condition of the circulation, and an unimpaired condition of the blood, that nitre should be employed. it has been considerably used in the inflammatory forms of our bilious remittent fever, during the exacerbations, in the form of nitrous powders.

4. Scurvy. in some cases of scurvy, nitre has been found of advantage; and, if the views of Dr. Garrod be correct, that a deficiency of the salts of potassa in the blood is a prominent characteristic of the affection, its beneficial operation may be explained. it was formerly supposed that the blood in scurvy was peculiarly defective in plasticity; but this has been found not to be true in most cases recently investigated; so that any objection to the use of nitre in that complaint, founded on its aplastic properties, must be considered as at least not generally applicable.

Of the use of nitre as a diuretic and diaphoretic, more will be said when we reach the classes characterized by these properties respectively.

5. Administration

The ordinary dose of nitre is from five to fifteen grains, repeated every hour, two, or three hours; from one to three drachms being administered in the course of the day. it may be given in powder or solution. The former method has been recommended, on account of the coldness produced during the solution of the salt in the stomach; but this advantage is more than counterbalanced by its liability to produce irritation, when taken in this method; and if cold is wanted, it may be more readily obtained by means of ice. it should, therefore, I think, in general, be preferably given in solution. Both in this form, and in that of powder, it is often associated with tartar emetic.

The nitrous powders, which have been much used in inflammatory and febrile diseases offering an indication for the mercurial impression, as in bilious fever and hepatitis, are prepared by mixing thoroughly one drachm of nitre, one grain of tartar emetic, and from four to sixteen grains of calomel, and dividing into eight powders, of which one may be given every two hours, or less frequently. The proportion of calomel is necessarily variable, to accommodate the variable circumstances requiring it.

The mode of exhibiting nitre in large doses has already been sufficiently considered When given in quantities exceeding fifteen or twenty grains, it should be dissolved in not less than eight fluidounces of liquid to a drachm of the salt; and still larger proportions of the menstruum may often be used with advantage.

Local Use. Nitre is sometimes locally used in sore-throat, either dissolved in water as a gargle, or mixed with sugar and allowed gradually to dissolve in the mouth. Employed in the latter method, it has the advantage of producing coolness by its solution in the saliva.

Another local application of nitre is in fumigation. For this purpose blotting-paper is employed, impregnated with nitre by being dipped once or oftener into a saturated solution of the salt, and dried after each immersion. The paper may be set on fire on a plate, or rolled up in a cylindrical form and placed in a candle-stick; and the patient may inhale the fumes as they rise, or simply breathe the air of the apartment. it may also be smoked by means of a tobacco-pipe. This fumigation sometimes affords great relief in the paroxysms of asthma. I have known a patient who found more relief from this than from any other remedy.

Nitre is also sometimes employed remedially for producing cold, for external use, when ice or cold water cannot be obtained. Five ounces of nitre, with the same quantity of muriate of ammonia, dissolved in a pint of water, may be introduced into a bladder, and applied to the head, in the headache or delirium of fever and meningitis, or elsewhere when required.