Cancer of the rectum can be usually felt, and hemorrhoids can be always seen, so that no difficulty should be experienced in the recognition of these cases.

Intussusception occurs mostly in children, and has, in common with dysentery, vomiting, mucous or bloody stools, colic, tenesmus, nervous unrest, and prostration, so that a differential diagnosis may be impossible for a few days. The more strict localization of an intussusception, which may sometimes be felt as a sausage-like mass, most frequently in the right ileum and hypochondrium, the greater frequency and persistency of the vomiting and pain, the presence visibly or palpably of the invaginated gut at the anus or rectum, soon enable the careful examiner to recognize the case.

PROGNOSIS.—The prognosis of dysentery varies between extremes. Some cases are so mild as to merit the remark of Sydenham concerning certain cases of scarlet fever: "Vix nomen morbi merebantur." They terminate of themselves under favorable hygiene without especial treatment. On the other hand, no known disease has a more frightful mortality than dysentery in some of its epidemics, especially in army-life. It was this class of cases which Trousseau had in mind when he called dysentery the most murderous of all diseases. Sixty to eighty may be the appalling percentage of death in these cases.

Under favorable surroundings the average mortality of dysentery amounts to 5-10 per cent., but is much influenced by the age and the general condition of the patient, as well as by the complications which occur in its course. Thus, Sydenham said of it over two hundred years ago, "It is not infrequently fatal to adults, and still more so to old men, but is nevertheless exceedingly harmless to infants, who will bear it for months together without suffering, provided only Nature be left to herself." But dysentery is by no means always harmless to infants, for in some epidemics this period of life has been visited with the greatest severity. Thus, Pfeilstücker reports of Würtemberg (1873-74) that the greatest mortality, 39 per cent., occurred at the age of one to seven years, and the least, 4 per cent., at the age of thirty-one to fifty years; and Oesterlen says of England that dysentery causes 20 per cent. of deaths from all causes in the first year of life.

Nor does the prevalence of a greater number of cases necessarily imply a heavier mortality. For Bianchi reports of Rome that cases of dysentery constituted but 2.28 per cent. of all the admissions into the Ospedale di San Spirito in 1873, while in 1874 the percentage increased to 3.68; yet the mortality of 1873 was 17.02 per cent., while that of 1874 was but 9.09 per cent.

Complications on the part of the nervous system, the status typhosus, pyæmia, and great prostration, necessarily render the prognosis grave, yet even these cases are not necessarily fatal. Thus, Jules Aron reports from the epidemic at Joigny (1876) a case of recovery after complete paralysis of the sphincter ani. The recognition and discharge of an hepatic abscess relieves the patient from the dangers of this complication. Peritonitis alarmingly aggravates the prognosis, and perforation is almost of necessity fatal.

PROPHYLAXIS.—The improved sanitation of modern times has already diminished the frequency and mitigated the severity of epidemics of dysentery; and this fact, which is only an accidental observation as it were, gives the clue to the means of its further prevention.

The selection of proper sites for camping-grounds, barracks, and hospitals, the prevention of overcrowding in tenement-houses, ships, and jails, the regulation of sewage, the care for the food and drink, the observation of the strictest cleanliness by authoritative control,—all these are general measures which suggest themselves in the prophylaxis of this or any disease.

In the management of individual cases the first precaution is to prevent the dissemination of the disease. Whether it be really contagious or not, every case should be managed, as Bamberger suggests, as though it were contagious; and this protection of others secures for the individual patient the most favorable hygiene.

The bedding must be frequently changed; the windows kept open to secure free ventilation, which, in the light of existing knowledge, is the only true disinfectant; and all the furniture of the sick-room, especially including the receptacles for the discharges, must be kept perfectly clean. For this purpose the best purifier is very hot water. The temperature of the sick-chamber, if it be subject to regulation, should never be allowed to sink below or rise above 65-70° F.