128 INOEGANIC AGENTS 



Dose.—U. & C, §ss.-i. (15.-30.); Sh. & Sw., 3ss.-i. 

 (2.-4.); D., gr.v.-xx. ).3-1.3). 



Action External.^Reivigevant 



Action Internal. — Stomach and Intestines. — Mtre 

 causes, in lethal doses, violent gastro-enteritis, often neph- 

 ritis, muscular weakness, coma, collapse and depression of the 

 circulation. The pulse becomes both slow and weak. There 

 is muscular weakness and paralysis. Potassium nitrate is 

 one of the most irritating salts of this group, but its toxic 

 effect depends upon the influence of the nitrate ion, and — 

 when concentrated — upon its " salt action " (see p. 140) in 

 withdrawing water from the tissues. 



Blood. — Toxic doses of nitre have a slight decomposing 

 action (hemolysis) on the blood. 



Heart. — Mtre is said to be more depressing to the heart 

 than the other potassium compounds. There is no basis for 

 this belief. 



Lungs. — The respiration is slowed by considerable doses 

 of potassium nitrate, and it exerts an antispasmodic action 

 by depression of the unstriped fibres of the bronchi. 



Kidneys. — Diuresis is the predominant medicinal ac- 

 tion of nitre. It may induce diuresis through its " salt ac- 

 tion " (see p. 140) but- in that case should escape unchanged 

 in the urine. Apparently little or none is thus eliminated, 

 except after large doses. In moderate doses the salt is 

 changed in the body. It is conjectured that it is first con- 

 verted into nitrites,, then into ammonia, and finally escapes 

 from the lungs as free nitrogen. 



The diuretic action is chiefly due to direct stimulation 

 of the renal cells. 



Potassium nitrate is more frequently prescribed than 

 any other potassium salt in veterinary practice, and is com- 

 monly considered one of the best febrifuges. Its only service 

 in fevers is as a diuretic. Its use as a febrifuge has there- 

 fore been long abandoned in human medicine. 



Administration. — Nitre is dissolved in a pail of drink- 

 ing water and kept constantly at the larger animal's disposal. 

 The salt is rendered harmless by dilution; vascular tension 

 and diuresis are increased by the water, and the solution is 



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