The same practitioner has found the medicine very useful in infantile diarrhoea. In cases attended with tormina, and glairy or bloody stools, he gives, morning and evening, an enema consisting of eight ounces of distilled water with one or two grains of the nitrate, according to the age; in other cases, characterized by nausea, and serous, green, or lien-teric passages, he administers by the mouth from the twentieth to the fifth of a grain dissolved in sweetened water. (Ibid., p. 355 ) The same practice has been employed with success in our indigenous cholera infantum, when there was good reason to suspect the existence of ulceration of the bowels; and it is certainly among the measures to which the prudent practitioner would be justified in resorting, in obstinate cases of the disease.

By M. Boudin, of Marseilles, the nitrate was recommended so long since as the year 183(5 (Gazette Med., No. 51, 1836), in enteric or typhoid fever, with a view to its curative influence upon the intestinal ulceration of that affection. He gave it either by the mouth or by the rectum, according as the disease appeared to be seated higher or lower in the alimentary canal; and sometimes he united both methods. He administered from a quarter to half a grain by the mouth, in the form of pill, and three or four grains, by enema, night and morning, dissolved in six fluid-ounces of water. This practice has been imitated by other physicians, but has not been generally adopted. I entertain strong doubts of its efficacy; as I do not believe that the nitrate, when swallowed, will reach the seat of the local disease unchanged; and they who are familiar with the position of the ulcerated surfaces, extending often throughout the whole length of the ileum, would scarcely admit that six ounces of fluid, thrown into the rectum of an adult, would come in contact with them.

In the diarrhoea of phthisis the medicine has been used with supposed advantage; but experience has not proved it to be more efficacious in this affection than other medicines habitually employed.

The late Dr. J. F. Peebles, of Virginia, found it remarkably efficient in certain cases of jaundice connected with an irritated condition of the stomach and small intestines. He gave from three-quarters of a grain to a grain twice a day, on an empty stomach. (Am. Journ. of Med. Sci., N. S., xviii. 59).

In reference to the cathartic effect which the nitrate of silver sometimes produces, it was recommended by Boerhaavc in dropsy; and the medicine is said to have been used advantageously in worms; but these applications of it are now seldom or never made.

2. For its effects upon the system at large, nitrate of silver has been employed chiefly in nervous affections. In some of these it has been carried to an enormous extent, with the effect probably sometimes of seriously injuring the coats of the stomach, and, in not a few instances, three of which at least have come under my own observation, of producing the indelible discoloration of the skin already described. Nor does this excessive use of the medicine, probably, contribute to the end in view. When given largely, the very irritation of the mucous membrane induced must interfere to some extent with its absorption; and by far the largest proportion is converted into chloride of silver, and passes out with the feces in this state, as proved by the experiments of Dr. Heller. In one instance, a boy aged thirteen took twelve grains daily for three months, without any effect on the system, or discoloration of the skin; and no trace of silver could be discovered in the blood or the urine: while the whole amount of the metal was found in the evacuations from the bowels. (See Am. Journ. of Med. Sci, N. S., xii. 476.) Nevertheless, that the silver does occasionally enter the circulation is, I think, certain; and it may be presumed to do so generally, though in minute quantities. As the absorption depends upon the solubility of the compound of silver formed in the bowels, and as this probably depends on the presence of an excess of albumen or an alkaline chloride in the alimentary canal, the less the amount of the nitrate given, the greater will be the excess of the solvent agents, and the consequent probability of its absorption. The practical inference from these views is. that the physician should limit himself to moderate doses of the medicine, as being at once safer, and likely to prove not less effectual. I have before endeavoured to explain the nature of the action, by which this medicine, and others belonging to the same subdivision, prove useful in nervous diseases. (See page 388.) It will be sufficient to repeat, in this place, that the silver probably acts by increasing the vital power of resistance of the nervous centres to irritant influences, and thus preventing the effects of their irritation, as exhibited in spasms and other irregular movements, and in neuralgic pain. The long period during which, according to the experiments of Orfila before referred to, silver continues to adhere to the tissues after its administration has been omitted, may serve in some measure to explain the permanency of its effects in nervous diseases.

Epilepsy is that one of the nervous affections in which the nitrate of silver has been given most frequently, and in the treatment of which it has the highest reputation. It is certainly among the remedies which have proved most effectual, so far as testimony can avail to decide the question. Even* one knows that epilepsy, from the very nature of its sustaining cause, is often quite incurable. That the nitrate of silver. therefore, should very frequently fail, is nothing more than might be expected. The great obstacle to its general use is its liability to cause discoloration of the skin, which is even more objectionable to most persons than the disease itself. The physician, dreading the responsibility of such a result, if he employ the remedy at all, is apt to do so ineffi-cientlv; either using it in too small a quantity, or not continuing it suffi-ciently long. Upon this point, however, he should always guard himself, by informing the patient or his friends of the possible result, and leaving the decision with them. The risk of the discoloration may be considered as extremely small, when proper precautions are taken. These will be mentioned.

Other nervous affections, in the treatment of which nitrate of silver has enjoyed considerable reputation, are chorea and angina pectoris. The former disease, however, is so readily curable by other less objectionable remedies, that it would not be justifiable to expose the patient to the risk, however small, of the cutaneous discoloration. But in angina pectoris, as in the cases of epilepsy, the choice may well be left to the patient; though the chances of a cure from the remedy are so slight, that little encouragement should be offered. To its use in hysteria, asthma, and pertussis, in which it might be considered as indicated by its influence on the nervous centres, the liability above alluded to should be deemed an all-sufficient objection.

A few years since it was employed by Wunderlich, with remarkable success, in a disease now known as locomotor-ataxy; and MM. Vulpian and Charcot have subsequently ascertained that, given in small doses, rarely exceeding half a grain in the day, it exercises a most favourable influence over this exceedingly intractable disease. The great drawback, in this, as in all the other nervous diseases requiring a long continuance of the remedy, is the liability of the patient to the very repulsive discoloration of the surface. It would be an unspeakable benefit to humanity, could means be found of preventing or removing this effect of nitrate of silver, without impairing its therapeutic virtues. The remedy has been used by M. Buchut, with entire success, in a case of idiopathic infantile paraplegia (Ann. de Therap., 1864, p. 225); and the same physician asserts that general progressive palsy, whether of the insane, or not thus complicated, sometimes gets well under the use of this remedy, in the dose of from one-third of a grain to about a grain daily. (Ibid., 1866, p. 274).