The offensive exhalation from a filthy alley which had been recently cleaned was the exciting cause of a fatal epidemic in a London school,13 and Levier recounts an epidemic caused by the drinking-water during the winter in Berne.14
13 Lond. Med. and Surg. Gaz., 1829, iv. p. 375.
14 Schweiz. Zeitschr. f. Heilk., iii., 1864, p. 140.
Nervous disturbance from other diseases may act as a cause. Leube reports a case of intermittent fever which was followed by an annual attack of cholera morbus preceded by febrile symptoms.15
15 Leube, Ziemssen, 1876, vol. vii. p. 148.
Malaria, sewer-gas, and sudden and powerful mental emotions are credited with the causation of some attacks.
PATHOLOGICAL ANATOMY.—In a few cases an examination of the body has revealed no phenomena sufficient to account for the symptoms, even when they have been the most severe during life. In these cases either the inflammation has not passed the first stage of development and the resulting hyperæmia has disappeared after death, or the irritation of the gastro-intestinal nerves has been sufficiently intense to cause death before the alimentary tract has undergone any consequent structural change.
Usually, however, there are evidences of a general gastro-intestinal catarrh: the mucous membrane is congested throughout and denuded of epithelium. The solitary glands are enlarged and Peyer's patches swollen and prominent. The blood is thickened and dark in color, and the serous membranes dry, sticky, and covered with desquamated epithelium. Indeed, the appearances may be identical with those observed in true Asiatic cholera. The kidneys are congested, sometimes enlarged, and the tubules devoid of epithelium. In protracted cases the general muscular system shows a beginning of granular degeneration.
In no case, however, can a positive diagnosis between Asiatic cholera and cholera morbus be made from post-mortem appearances.
SYMPTOMS.—The attack is usually sudden in its onset, but in some cases is preceded by nausea, thirst, loss of appetite, and slight general distress for some hours, or it may come on in the course of some gastro-intestinal disturbance. Frequently it is developed during sleep, particularly after midnight, the patient being aroused by a feeling of pressure at the pit of the stomach, which is followed by nausea and violent and incessant vomiting with intense pain, the contents of the stomach being ejected with great force.