332 MATER i A MEDIC A AND THERAPEUTICS. 



Non-officinal Preparations. 



1. Salicinum. Salicin, C 13 H 18 7 . A neutral principle in silky 



acicular crystals, or white tables ; odourless, bitter. 

 Solubility, 1 in 20 of water. Dose, 5 to 30 gr. 



2. Acidmn Salicylicum, C 7 H 6 3 , or H 2 .C 7 H 4 03. Source. 



Prepared from the oil of Gaultheria procumbens (Winter 

 Green), or commercially by passing a stream of Carbonic 

 Acid over a heated mixture of Carbolic Acid and Caustic 

 Soda, decomposing by Hydrochloric Acid, and purifying. 

 Characters. Light acicular crystals ; odourless, but irritant 

 to the nostrils; with a sweetish taste. Solubility, 

 1 in 760 water ; 1 in 4 of spirit. 

 Lose. 6 to 30 gr. or more. 



From Acidum Salicylicum is prepared : 



Sodas Salicylas. Na 2 .C 7 H 4 3 . Source. Made by neutral- 

 ising the Acid by Bicarbonate of Soda in water ; or 

 as the acid without the final decomposition. 



Characters. Shining silky tabular crystals, or a white 

 crystalline powder, odourless, with a sweetish 

 unpleasant taste. Solubility,' 1 in 1 of water. 



Dose. 10 to 30 gr. 



'ACTION AND USES. 



1. IMMEDIATE LOCAL ACTION AND USES. 



Externally. Salicylic acid acts as an antiseptic and dis- 

 infectant, not inferior to carbolic acid. At the same time it 

 stimulates the local circulation. It is extensively used as a 

 surgical dressing in the form of cotton wool impregnated with 

 the acid by the aid of glycerine. On the contrary, salicylate 

 of soda has no antiseptic or disinfectant power, unless combined 

 with a mineral acid to liberate the salicylic acid. Salicylic acid 

 in powder, diluted with talc, is a anhidrotic, checking local 

 perspirations of the feet, or the general perspirations of phthisis. 

 Neither substance is absorbed by the unbroken skin. 



Internally. Salicylic acid causes sneezing and cough when 

 applied to the nose, or inhaled, like benzoic acid; and when 

 admitted to the stomach, it is also a local irritant, causing heat, 

 pain, nausea, and vomiting, unless in moderate and well-diluted 

 doses. The soda salicylate is very much less irritant, and may 

 be freely administered if pure. The latter drug is used for 

 sarcinous vomiting, and in some cases of chronic dyspepsia with 

 decomposition. Salicin is easily borne by the stomach. In 

 the bowel it is converted into saligenin (C 7 H 8 02) and glucose ; 



