1. Narcotic Antispasmodics

Those which deaden the sensibility and irritability of the nervous system generally, and thus allay that irregular and violent contraction of muscular fibre which constitutes what has been denominated a true spasm. Amongst this class may be enumerated the narcotics, particularly Opium and Belladonna. The former generally affords more speedy relief, but it is not of so permanent a character as that obtained from Belladonna. The operation of all this class is attended by more or less subsequent narcotism.

2. True Or Specific Antispasmodics

This class includes Assa-ftida, Valerian, Musk, Castor, Galbanum, &c, medicines which relieve spasms without producing any other sensible effect on the system. It is generally considered that they produce benefit by their stimulant action; but how this can be the case, when the spasm itself, in many cases, arises from excessive stimulus or irritation of muscular fibre, remains to be explained. "When, however, the spasm arises, as it doubtless often does, from deficient nervous energy, this explanation is much more satisfactory.

3. Tonic Antispasmodics, or those agents which establish a healthy tone of the nervous system. This class includes the Nitrate of Silver; the Oxide of Silver; ammoniated Copper; the Sulphate, Oxide, and Valerianate of Zinc, &c. Remedies of this class are of little or no service during a paroxysm; the intervals being the proper time for their administration, and their utility being confined to preventing a recurrence of the spasm. They appear to operate by establishing a tonicity and healthy condition of the nervous system, thus preventing the occurrence of abnormal irritability of the nerves, and consequent inordinate contractions of muscular fibre. They all require to be persevered in for a lengthened period; indeed, few of them exercise any permanent benefit, if not continued for weeks, or even months.

4. Stomachic Antispasmodics, or those agents which, by correcting a deranged state of the stomach and digestive organs, operate indirectly in establishing a healthy condition of the nervous system. Visceral derangements are a frequent cause of great nervous irritability; and, as a consequence, a tendency to irregular muscular contractions in various parts of the body. This deranged state of the digestive organs may arise from so many causes, that the practitioner must examine minutely into each case, before determining on the remedy, or class of remedies, likely to prove most serviceable: thus, if it arise from a vitiated state of the biliary secretion, a mild course of Mercury, or even a single dose of Calomel, may be sufficient; if from abnormal acidity, alkalies are indicated; if from the presence of worms, anthelmintics; but it may be laid down as a general rule in all spasmodic diseases, that strict attention to the state of the alvine secretions, and of the digestive functions, is indispensable.

2907. In the practical application of Antispasmodics, the only point which requires particular notice is the necessity of dis-

tinguishing clearly between spasm and inflammation, a point of occasional difficulty. In spasm, as compared with inflammation, it may be stated generally, that the pain comes on more suddenly, is of a more acute and distressing character, is relieved by slow and continued pressure (whilst that of inflammation is increased), is accompanied by intervals of comparative or positive ease; the pulse in the meantime is not accelerated in proportion to the amount of pain, and wants that peculiar, wiry throb which accompanies inflammation of serous membranes. For the other distinguishing marks, the reader is referred to the lectures of l)rs. Watson, Graves, &c. It is only necessary to add, that spasm will be relieved by the above-named remedies, sometimes in a marked and sudden manner, whilst the pain of inflammation will be either only slightly eased, or in some cases even increased, by them.