This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
A reasonable argument may be given for its employment, for a main fact in the disease is profuse discharge by osmosis from the vessels of the intestinal tract into the alimentary canal; this by itself can determine the cyanosis, shrunk features, blood stasis, etc. It depends upon a change in the albuminous constituents of the blood, and is increased by desquamation of intestinal epithelium, while by saline injections the physical conditions may be so far altered as to lessen such osmosis. Both rectal and venous injections have been used, and benefit also has been traced to salt given by the mouth in cases when the power of absorption has been retained.
During an epidemic at St. Petersburg (1830) salt water and salt milk relieved as much as any other remedies. In 1835, at Paris, Bracton reported fifty cases of Asiatic cholera treated with common salt, and only one was fatal; two tablespoonfuls were given dissolved in 6 oz. of water. Chomel, Aran, Richard, and others reported good results from the same treatment in the epidemic of 1865. On the other hand, Husemann concludes that the use of salt has no really good effect, and states that its intravenous injection has sometimes caused asphyxia. The question cannot yet be considered decided.
For Dysentery, the sulphate of soda has been much commended by American writers: 1 dr. is given with 1/6 gr. of morphia every two hours, until natural, though loose, evacuations occur; this treatment is said to control the malady in two or three days (New York Medical Record, February, 1872).