542 



seems to me to be a new acid, and this I hope soon to be able to 

 ascertain. 



When the stearopten is gently warmed with oil of vitriol it 

 dissolves, and, on cooling, solidifies into a crystalline mass. This 

 new compound, which is a copulated acid, dissolves readily in hot 

 water, and, on cooling, is deposited in large scaly crystals, of a 

 mother-of-pearl lustre. It forms both a crystallizable lead and 

 baryta salt. 



When the stearopten is distilled with a mixture of peroxide of 

 manganese and sulphuric acid, it yields a substance exceedingly 

 analogous in almost every respect to the thymb'il obtained by Lalle- 

 mande by subjecting the stearopten of oil of thyme to similar 

 treatment. As the details of Lallemande's experiments have not 

 yet been published, it would be premature to pronounce with abso- 

 lute confidence on the identity of the stearoptens from the Ptychotis 

 and oil of thyme ; but if not identical, as I rather apprehend they 

 are, they are certainly extremely similar bodies*. 



Gum of the Gardenia lucida, Roxb. (the Decamalee GumofScinde). 



The specimen of this gum on which I operated was evidently 

 very old. It formed a hard, dry mass, of a dark brown colour, 

 with numerous patches of a greenish-yellow matter disseminated 

 through it. It had but a faint odour, unless freshly fractured or 

 gently heated, when it smelt like the urine of the cat. 



A comparatively recent specimen of this gum, which I saw in the 

 hands of the late Dr. Stocks, had merely the consistence of candied 

 honey, and an exceedingly offensive odour. Dr. Stocks informed 

 me that the fresh gum was employed as a dressing for wounds, as 

 it kept off the flies. The resin was digested in strong spirit of 



* Since this paper was communicated to the Royal Society, a notice of the 

 Ptychotis. oil, by Dr. Haines, of the Bombay College, was read before the last 

 meeting of the Chemical Society. Dr. Haines has generally arrived at similar 

 conclusions to my own. He regards, however, the carbohydrogen portion of the 

 oil not as isomeric with oil of turpentine, but as C 20 H 14 . 



His formula for the stearopten is the same as that given in this paper ; and he 

 regards it as identical with Lallemande's thymole. 



Dr. Haines, however, appears not to have observed the crystalline acid pro- 

 duced by the action of nitric acid on the stearopten. 



