C13H18O7=285.33. A neutral principle (glucoside) obtained from several species of Salix and Populus (nat. ord. Salicaceae). Synonym. - Willow.

Habitat

Europe, naturalized in North America; cultivated.

Source

1) Make a strong decoction of willow bark. (2) Remove the tannic acid by warming and agitating the decoction with Lead Oxide. (3) Evaporate the solution. Salicin crystallizes out, and is purified by repeated solution, and crystallization.

Characters

Colorless, or white, silky, shining crystalline needles, or a crystalline powder, odorless, and having a very bitter taste. Permanent in the air.

Solubility

In 28 parts of water, and in 30 parts of Alcohol; almost insoluble in Ether or Chloroform.

Dose, 5 to 30 gr.; .30 to 2.00 gm.

Acidum Salicylicum. Salicylic Acid

Hc7h5o3=137.67. An organic acid, existing naturally, in combination, in various plants, see Oleum Gaultheriae and Oleum Betulae Volatile; but most largely prepared synthetically from Carbolic Acid.

Source

Made by combining Sodium Carbolate with Carbon Dioxide Gas. Thus, dry Carbon Dioxide is passed through Sodium Carbolate heated to 428° F.; 220° C.. 2NaC6H5O+Co2=Na2C7H4O3 (Sodium Salicylate), +C6H6O (Phenol). This is treated with Hydrochloric Acid. Na2C7H4O3 +2HCl=2NaCl+Hc7h5o3 (Salicylic Acid).

Characters

Light, fine, white, prismatic needles, or a light, white, crystalline powder; odorless, having a sweetish, afterwards acrid taste, and permanent in the air.

Solubility

In about 450 parts of Water, and in 2.4 parts of Alcohol; also soluble in 2 parts of Ether, 2 parts of Absolute Alcohol, and 80 parts of Chloroform. Resembling Artificial Salicylic Acid - Strychnine, but the crystals of Strychnine are larger, colorless, non-irritating, less soluble, and the solution is very bitter.

Incompatible. - Spirit of Nitrous Ether.

Impurities

Orthocreosotic, metacreosotic, and paracreosotic acids, only in artificial salicylic acid. In the best specimens they are absent.

Dose, 5 to 60 gr.; .30 to 4.00 gm.

Sodii Salicylas. Sodium Salicylate

NaC7H5O3=159.67.

Source

Obtained by acting on Sodium Carbonate with Salicylic Acid. 2Hc7h5o3+ Na2Co3=2NaC7H5O3+H2O+Co2. The solution may be strained through muslin and heated to expel the Carbon Dioxide.

Characters

A white, amorphous powder, odorless, and having a sweetish, saline taste. Permanent in cool air.

Solubility

In 0.9 part of Water, and in 6 parts of Alcohol; also soluble in Glycerin.

Incompatible. - Hydrobromic acid, for sodium bromide is formed and salicylic acid is precipitated.

Impurities

Orthocreosotic, metacreosotic, and paracreosotic acids.

Dose, 5 to 60 gr.; .30 to 4.00 gm.

Lithii Salicylas. Lithium Salicylate

(LiC7H5O3=143.68.)

Source

Obtained by heating Salicylic Acid, Lithium Carbonate, and

Water, until the effervescence ceases, filtering and evaporating. Li2Co3 +2Hc7h5o3=2LiC7H5O3+H2O+Co2

Characters

A white, or grayish-white powder, odorless, and having a sweetish taste; deliquescent on exposure to air.

Solubility

Very soluble in Water and in Alcohol.

Dose, 1 to 15 gr.; .06 to 1.00 gm.

For Bismuth Salicylas see p. 183, and for Salol see p. 481.