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III. Examination of the Crystalline Dejjosit uihich forms in Oil 

 of Bitter Almonds. Bij John Stenhouse, LL.D., F.R.S* 



WHEN oil of bitter almonds is kept for some time in 

 loosely-stoppered bottles, a crystalline deposit not uu- 

 frequently forms in it, especially if tbe oil is exposed to the 

 influence of the hght. So long ago as 1823, M. Stange declared 

 this crystalline deposit to be simply benzoic acid produced by the 

 oxidation of the oil, a statement which was confirmed in 1830 

 by Robiquet and Boutrou-Challard. {Ann. de Chini. et de Phys. 

 vol. xliv. p. 364.) It does not appear, however, that any of 

 these chemists subjected the supposed benzoic acid to the test of 

 analysis. Subsequently the late Dr. Jonathan Pereira, in the 

 first edition of his Elements of Materia INIedica, page 1107, 

 stated that he had met with " three kinds of a crystalline sub- 

 stance from oil of bitter almonds, difi"ering essentially from each 

 other and from benzoic acid." These deposits were examined 

 by Dr. Pereira, and one of them, that marked No. 3, by Dr. 

 Letheby. None of them were subjected to analysis, but they 

 were tested by the action upon them of oil of vitriol, caustic 

 potassa, &c. These crystalline deposits were given to Dr. Pereu-a 

 by Mr. George Whipple, who kindly furnished me a few weeks 

 ago with no fewer than ten different specimens of a similar 

 character which had formed in as many portions of oil of bitter 

 almonds. The weight of the crystals exceeded three ounces. 



The crystals had a deep yellow colour, and were strongly im- 

 pregnated with oil of bitter almonds. As much of the oil as 

 possible was removed by strongly compressing the crystals 

 between folds of blotting-paper. The crystals were then digested 

 with boiling water, in which they readily dissolved. After 

 repeated solutions and crystallizations they presented the usual 

 characters of benzoic acid. On analysis, 0''1215 grm. substance 

 dried at 212° F., when burnt in a current of oxygen gas, gave 

 1"069 carbonic acid and 0'2005 water = 



100-000 100-000 



The silver salt was prepared by neutralizing the acid with 

 ammonia and then adding a solution of nitrate of silver. When 

 subjected to analysis, 0-3883 grm. salt gave 0-525 carbonic acid 

 and 0-317 water. 



* Commtuiicated by the Author. 



