Even sodium chloride is poisonous under certain circumstances, and Jacques Loeb believes that the function of potassium and calcium salts in the blood and in sea-water is to prevent penetration of cells by too much sodium chloride. A number of cases of poisoning from concentrated saline used intravenously or by rectum instead of normal saline have been reported, the symptoms being nausea, vomiting, diarrhea, maniacal delirium or coma, fever up to 104o F., collapse, and death. In a fatal case of a woman given 1920 grains (64 gm.) by hypodermoclysis in mistake for normal saline, Combs noted crenation of the red cells in the fresh blood. Barlow reports that the drinking of a pint or more of the saturated solution is a common method of committing suicide in Chekiang Province, China. Campbell cites a case of death in a boy of five who was given a pound instead of a tablespoonful of salt in a quart of water as an enema for worms. Brooks reports death in an adult from an enema of a strong solution. The author has received a report of death in one infant from a colon irrigation of a 1: 16 solution, and gangrene in another from hypodermoclysis with the same liquid, which was labeled "normal saline."

The relation of edema to salt retention is a highly important one. Bryant reported the case of a physician who developed serious edema of the legs after eating very large quantities of salt with his meals for several weeks. Stoppage of the habit resulted in cure. Sodium chloride should not be administered as an infusion or rectal injection in parenchymatous nephritis, eclampsia, or any condition with edema.

On the other hand, too prolonged salt-free diet may result in indigestion, vomiting, absence of acid in the gastric juice, weakness, nervous irritability, and cachexia. The author has seen two cases of nephritis with marked edema, in one of which a salt-free diet resulted in convulsive twitchings of the muscles all over the body which were relieved by giving salt, and in the other of which it was impossible to obtain diuresis except when salt was given. It is estimated that an adult requires from 2 to 3 grams of sodium chloride a day.

Bonninger states that salt has a marked inhibitory action on the secretion of gastric juice, and Hamburger shows that it inactivates pepsin. Best finds 2 glasses of normal saline an effective cathartic, and Miiller an intravenous of 5 c.c. of 10 to 15 per cent. two or three times a day effective against hemoptysis.

A peculiar effect of hypertonic sodium chloride (1.5 c.c. of 30 per cent. solution) intravenously is the protection of guinea-pigs against anaphylactic or proteotoxic shock. It acts by lowering the irritability of smooth muscle (Dale, Zinsser, Lieb). (See also Saline Infusion.)

Sodium Bicarbonate (Sodii Bicarbonas)

For alkalinity, the favored salt is sodium bicarbonate (NaHco3). This salt is extensively employed both externally and internally. Five grains (0.3 gm.) will neutralize 6.2 minims (0.4 c.c.) of hydrochloric acid (U. S. P.), about 22 minims (1.5 c.c.) of diluted hydrochloric acid, and 1 1/2 ounces (45 c.c.) of gastric juice of 0.3 per cent. strength. The alkalinity of its solution increases on standing, owing to the loss of carbon dioxide. On boiling it sets free carbon dioxide with effervescence and loses 37 per cent. of its weight. Externally, in solution, it is a solvent for dried exudates, such as the crusts in seborrheic eczema; and either in solution or paste is a soothing application in erythema, urticaria, itching, insect-bites, and burns. It is not caustic. To mucous membranes its solutions are soothing, and they act as solvents for thick mucus.