It was only after many years of laborious investigation that the appropriate lesion was affixed to a symptom so well understood and described in its clinical aspects. The first conception of abdominal and intestinal inflammation had no relation to diarrhoea. Under the name [Greek: eileos], Hippocrates described abdominal symptoms of intestinal obstruction and inflammation. For Sennert (1641) inflammation of the intestines meant peritonitis. Bonet (1679), Hoffman (1710), and Boerhaave (1758) included under this head peritonitis, ileus, and all febrile and painful abdominal affections. Sauvages (1763) and Morgagni (1779) gave in detail the symptoms of peritonitis and called the disease intestinal inflammation—enteritis. In 1784, Cullen made an advance in subdividing enteritis into e. phlegmonodoea and e. erythematica—the one involving the entire wall of the intestine and the peritoneum, the other the mucous membrane lining the intestine. John Hunter (1794) first fixed the place of peritonitis as a distinct affection from inflammation of the mucous membrane of the intestines.2

2 J. Hunter, A Treatise on the Blood, Inflammation, and Gun-shot Wounds, London, 1794, p. 284.

Up to this time constipation was the chief symptom of enteritis. The meeting of the streams, the affixing the symptom diarrhoea to its appropriate lesion, was brought about hypothetically at first by J. Carmichael Smith in these words: "I think it is probable (for we can have no positive evidence of the fact) that in diarrhoeas from catching cold the villous or interior coat of the stomach is sometimes slightly inflamed."3

3 Paper read Jan. 8, 1788, Med. Communications, London, vol. ii., 1790, p. 168.

On the Continent enteritis soon after this was limited in its meaning by Pinel (1798) to inflammation of the mucous membrane of any part of the intestines. He gave the name catarrhal diarrhoea to the same condition. A still further restriction of its meaning was made by Broussais (1821), who defined enteritis to be an inflammation of the mucous membrane of the small intestine; he gave the name colitis to the same disease in the colon. This distinction was adopted by Rostan (1826), Andral (1836), C. H. Fuchs (1846), G. B. Wood (1852), Wunderlich (1856), Grisolle (1865), Flint (1866), and Aitkin (1868). According to the views of some authors, chiefly English, as Copland (1844), Bristowe (1871), Roberts (1874), Habershon (1879), enteritis includes inflammation of the serous as well as of the mucous coat of the intestines.

Niemeyer (1864), Jaccoud (1869), Leube (1875), Bartholow (1880), and most German and French authors prefer the name intestinal catarrh as applied to inflammation of the mucous coat; inflammation of the serous coat is peritonitis; the word enteritis is abandoned as involving a pathological error.

NATURE AND CLASSIFICATION.—Catarrh of the intestines is an inflammation of the mucous membrane of the intestinal tract. There are various peculiarities of the catarrhal process due to the anatomical structure of the parts involved, the presence of open glands, lymphatic follicles, etc. This disease is to be distinguished from inflammation of the serous coat of the intestine (peritonitis). The two are quite distinct in their etiology, pathological anatomy, and symptomatology, although they have been often confounded under the same name, enteritis.4 As so much confusion prevails as to the proper meaning of enteritis, it is best to abandon the word altogether.

4 For cases called enteritis in which the lesions of peritonitis were found, see Hamilton, Edin. Med. Journ., vol. ii., 1857, p. 304; also Breed, Chicago Med. Examiner, Oct., 1869, p. 579.

Diarrhoea is still regarded by some authors (J. J. Woodward) as synonymous with intestinal catarrh; by others it is considered separately as a disease distinct from catarrh. Habershon describes the lesions of catarrhal diarrhoea and mucous enteritis almost in the same words.5 It is an unscientific method to take one symptom of a pathological state, to erect it into a disease, subdividing it into varieties which are but differences in the intensity of its manifestation, and to assign to it no fixed lesion. Diarrhoea is in reality but a sequence and symptom of hyperæmia or inflammation of the intestinal mucous membrane.

5 Such a method of treating the subject involves a repetition, with an inversion, of the same description. Thus, catarrhal diarrhoea has as its lesion mucous enteritis; mucous enteritis has for its symptom (catarrhal) diarrhoea.