234 HYDRATES AND CARBONATES OF THE ALKALIES. 



INORGANIC SALTS. 



Sodium Chloride, in dilute solution, causes the tissues to become swollen and soft- 

 ened; whereas, in concentrated solutions, it tends to extract water from the tissues. 

 Consequently, the red blood-corpuscles become swollen when in hypotonic solutions, 

 and shrink in hypertonic solutions. This same characteristic action of sodium chlo- 

 ride on muscle tends to injure the vitality of the muscle-cell, and on mucous mem- 

 branes tends to interfere with function. The blood is concentrated by hypertonic 

 solutions, and made more liquid by hypotonic solutions, though in either case normal 

 conditions are soon restored by osmosis of tissue-lymph. 



Salt solutions in the blood augment the flow of urine through increased capillary 

 pressure in the glomerulus. 



Salt solution, in the isotonic form, 0.9%, is used chiefly to compensate for loss of 

 blood, as in hemorrhages and in cholera; and for flushing the system in uraemia. 



Potassium Chloride depresses the central nervous system, especially the great cen- 

 ters in the medulla; it also has a toxic action on the heart. 



Potassium Salts are not to be administered for the potassium effect, as this effect 

 is not elicited -when the drug is given by stomach. 



Ammonium Chloride, when injected subcutaneously or intravenously, stimulates 

 the central nervous system in the same manner as strychnine, but this action is not 

 elicited by oral administration. When given by mouth, it is absorbed readily by the 

 stomach and intestines, and has been thought to stimulate the mucosa of the stomach 

 and intestines. In the bronchi, however, application must be made direct, as the epi- 

 thelium of the lungs is impermeable to the ammonium ion. 



Ammonium chloride is thought to be good for gastric catarrh; and, in the form 

 of nascent vapor, is used for bronchitis. 



Ammonia Gas, when inhaled, irritates the nasal and bronchial mucosa, produc- 

 ing thereby a reflex stimulation of the vasomotor center, with a resulting vasoconstric- 

 tor action and a temporary rise in blood-pressure. It is thus of value in syncope. The 

 inhalation is dangerous in higher concentration than i : 2000. 



Ammonium Carbonate is a mild irritant to the stomach. When given in solution 

 it is thought to be of value in the treatment of flatulency. 



The ammonia vapor from the carbonate is used in "smelling salts" for its reflex 

 stimulation. It is probably of some use in impending attacks of faintness. 



Ammonia salts are rapidly excreted. 



HYDRATES and CARBONATES of the ALKALIES. 



The pharmacodynamics of this group is due entirely to the non-metallic ion. 



These substances have a soapy, detergent feeling in the mouth ; are neutralized in 

 the stomach, unless in large quantities ; are absorbed rapidly from the intestines, as 

 carbonates or in combination with proteins; increase the relative alkalinity of the 

 blood ; and are promptly excreted as alkaline salts from the kidney. 



Concentrated solutions are strongly escharotic; especially is this true of the hy- 

 drates. 



