The disease consists in a membranous substance, lining not only the trachea above its divarication, but also its minutest branches, though the larger parts of the tube are first affected. It has been considered as a spasmodic disease by some, as it attacks suddenly, and is relieved by the warm bath and asafoetida; and as inflammatory by others, who rest, with equal security, on the cough preceding, and the utility of bleeding. In the early period it is undoubtedly inflammatory, but this stage is short and transitory; the exudation soon commences, and the remedies for inflammation lose their efficacy. It may be perhaps asked, in what, then, does the disease in its progress consist ? Certainly not in spasm, but in this peculiar exudation, of which we have scarcely any other example: and the more general ideas of spasm and inflammation have, we fear, misled practitioners in the treatment of the disease. The exudations, which are usually the consequence of inflammation, agglutinate contiguous parts, not in the form of a membrane, but of cellular texture. It is thus in the lungs when united to the pleura, and in every instance of adhesive inflammation. A preternatural quantity of mucus hardens in masses, but not in membranes; for the mucus of the bronchial glands in catarrhs and asthmas, never assumes a membranous form. In fact, the inflammatory effusion consists of the gluten of the blood diluted with the serosity: the croupy membrane is a peculiar secretion. The labours of physiologists have discovered lately a new ingredient in the blood, which they have called fibrin; which concretes in a fibrous substance, sometimes membranous, and has even been suspected of possessing a por-tion of irritability. It is undoubtedly this substance which is effused; but why inflammation, at this particular period, should occasion the exudation of fibrin rather than of gluten; why this should occur at an age when fibrin is not peculiarly abundant; and why a portion of the blood, which contains the largest share of azote, should be separated at a time of life when this principle is in a small proportion; are difficulties that we cannot surmount. The chemistry of the animal fluids is in its infancy. We know not the effects of the "play of affinities"in the fluid parts of the system; and, by some unexpected combinations, azote may be separated in constitutions that appear to contain the smallest share of it. Thus we cannot detect sulphur in the animal system; yet we find it separated in the intestinal canal, and making a large proportion of the fluids of some malignant ulcers and cancers. The whole is at present involved in obscurity.

To detail the progress of a disease which generally goes on from bad to worse, or to estimate the period when nature can no longer bear up against the accumulations that obstruct respiration, would be useless: the distinction it is of more consequence to consider. The peculiar breathing is not the criterion of the complaint, for it occurs often in children without any bad consequence, and in persons of every age. Experience can see a distinction in the appearances which language cannot convey; but, in general, it may be considered as true, that the clangous inspiration if not relieved within twenty-four hours, or, if relieved, recurring within twelve, is of the croupy kind, especially in children under four years. The asthma of infants has undoubtedly been mistaken for croup; but in those we think the respiration is attended with some rattling noise, while in croup it is clear and shrill. See Asthma spasmodicum. Many cures have been re-portedof croup, which were certainly cases of this kind; for those who have been able to distinguish the disease, have repeatedly failed with the same remedies. It is not infectious, but it seems to prevail in particular situations; and in families it has affected all the children about a certain age.

We have said that it is for a short period inflammatory, and this we judge from the effects of active, decisive bleeding. If there be any truth in medical observation, a large bleeding, immediately on the attack, has cured the disease. At a future period scarcely anything has succeeded, though a few victims have been rescued.

Emetics, topical bleeding with leeches, blisters, and purgatives, have been repeatedly tried, scarcely in any instance with success. We had long since determined to neglect these and to pursue an opposite method, viz. by a cordial and sudorific plan to endeavour to direct the morbid fluids to the surface, led by some relief apparently obtained by a quack medicine, which certainly had no other powers. This method would have been attempted, had not bold empiricism introduced another, viz. large and repeated doses of calomel. Even to very young children five or six grains are given every two or three hours, till a discharge of a green bilious matter comes on; and the relief, it is said, soon follows. We have some confidence in the reports we have received of the success of this medicine, though in our hands it has failed; and the rapidity with which mercurials of all kinds break down the denser parts of the blood, renders it, in our opinion, a remedy of great apparent utility. The thin green bilious discharge seems an evidence of this effect. Strong mercurial frictions might perhaps be at the same time employed.

Angina erysipelatosa, mucosa, epidemica, angi-nosa, exanthematica. mucous quinsy. see scar-i.atixa anginosa.

Angina parotidaea. The cynancht parotidaea of Cullen; catarrhus bellinsulanus, ourles, and orcillons,of other authors. After a slight inflammatory fever, the parotid and maxillary glands swell sometimes rapidly, and to a considerable size; but they seldom suppurate, and the disease requires no particular remedy. The fever is decisive in its attack, and appears of a specific nature. What leads more strongly to this opinion is, that the swelling sometimes ceases suddenly, and is transferred to the testes in the male, and to the mammae in females. We have, however, seen it twice pretty generally epidemic among children, without observing either metastasis. Twice in adults we have seen an instance of the former, and the swelling yielded to the common remedies. In the neck, it has been usual to keep the part warm; to give nitre and purgatives, and to rub in mercurial ointment. Nothing is, however, necessary; and those who have been most neglected, have been soonest restored to health. Keeping the swelled neck warm is always improper; nor does there seem the slightest reason to suspect a translation to the brain. Gooche's Cases and Remarks, p. 74 - 76, and Appendix, p. 13. Cullen's First Lines, edit. 4, vol. i. p. 303.