292 INORGANIC AGENTS 



official one per cent, solution is. not explosive unless it 

 becomes concentrated by evaporation to an extent exceeding 

 10 per cent. 



Properties. — A clear, colorless liquid, possessing the 

 odor and taste of alcohol. Caution should be exercised in 

 tasting it, since even a small quantity is liable to produce a 

 violent headache. Spec. gr. .826 to .832. 



Dose,—R., 3ss..i. (2.-4.); D., Uti--"- (.06-.12). 



ACTION OF THE NITRITES. 



Externol. — Spirit of nitrous ether, like ether, produces 

 a cooling and local anaesthetic action, owing to its evapora- 

 tion upon the skin. Amyl nitrite has a slight depressing 

 action upon the peripheral ends of the sensory nerves. 



Internal. — The actions of spirit of nitrous ether, amyl 

 nitrite, and nitroglycerin are essentially the same. Spirit 

 of nitrous ether should contain 4 per cent, of ethyl 

 nitrite. Analyses of 68 samples taken at random from drug 

 stores, resulted in showing that a teaspoonful of the best 

 specimen contained as much ethyl nitrite as a pint of the 

 worst, with all manner of variations between these extremes. 

 To be of value as a nitrite, sweet spirit of nitre should be 

 freshly prepared by a reliable chemist. 



Circvlcdion. — The important action of the nitrites centres 

 upon the heart and blood vessels. The arterioles all over 

 the body become relaxed and blood tension is lowered by 

 the nitrites. This action is no doubt peripheral, but whether 

 due to the impression upon the vasomotor ganglia or mus- 

 cular fibres in the walls of the vessels is uncertain. The 

 heart beats more rapidly in consequence of the lessened 

 vascular resistance, and because a diminished blood pres- 

 sure depresses the vagus centre and often stimulates the 

 accelerator. The arterioles being dilated in the heart, as 

 elsewhere, there follows an increased cardiac blood supply, 

 nutrition and force. The nitrites also stimulate the cardiac 

 ganglia, and increase the force as well as the rapidity of the 

 heart. This is shown by the fact that in small doses blood 



