LABIATE. 113 



> 



has an aromatic thyme-like odour and a warm, pungent but 

 scarcely caustic taste. It dissolves sparingly in water, requiring 

 at 35° 0. 1,100 to 1,200 parts for solution, but is soluble in half 

 its weight of alcohol, ether^ and chloroform, in 2 parts of soda 

 solution sp. gr. 1*1 6, and freely in benzol, benzin, carbon 

 disulphide, glacial acetic acid, and fixed and volatile oils. It 

 forms with soda a crystallizable and readily soluble compound, 

 and does not change the colour of a solution of ferric chloride. 

 Symes{]879) ascertained that on being triturated with one-half 

 to ten times its weight of camphor, a colourless syrupj^ liquid ia 

 obtained, but it does not liquefy with chloral hydrate. According 

 to Gerrard, the strongest aqueous solution of thymol available 

 ia 1 in 1,000, and a solution of 4 grains of it in a fluid ounce of 

 alcohol is miscible with water without becoming turbid; 

 3 grains of thymol are dissolved by 1 grain of caustic soda and 

 1^ grains of caustic potash. Solid fats, when heated, are 



excellent solvents of thymol. A solution of 1 part of thymol 

 in 100 parts of warm glycerin remains clear. Thymol is also 

 soluble in 4 parts of cold sulphuric acid ; the solution has a 

 yellowish colour, and, on being gently heated, becomes rose-red. 

 On pouring this solution into 10 volumes of water, digesting 



^ the mixture with an excess of lead carbonate, and filtering, 

 ^ the liquid becomes Aaolet-blue on the addition of ferric chloride. 

 This reaction is due to sulphothymolic acid^ C^°H^*SO*, discovered 

 by Lallemand (1853). Hummarsten and Eobert (1881) give 

 the following as the most delicate test by which one-millionth 

 of thymol may still be detected : Mix the liquid with one-half 

 of its volume of glacial acetic acid, then with at least an 





equal volume of sulphuric acid, and warm gently, when a bright 

 reddish-violet colour is produced which is not destroyed by 

 boiling. According to Hirschsohn (1881), a solution of thymol 

 in 60,000 parts of water is rendered turbid by bromine-water, 

 but, according to Hammarsten, the precipitate is not crystalline 

 Uke tribromophenoL {Stille and Maisch.) 



iJ Chemical composition. — The volatile oiL oi Thi/mus Serpf/iliim, 

 Linn., according to E. Buri (1879), contains two phenols which 

 |g^ do not congeal at — 10° C, and of which one imparts a yellowish- 



IIL~16 



