— 78 - 



of citral in oils of lemon and orange. In addition to this they propose 

 the colorimetric method of Hiltner 1 ). The citral-content test of orange 

 oil has for its principal object the detection of any added citral or oilof 

 lemon. If the citral-content ascertained by Hiltner's method exceeds 0,7 %> 

 such an adulteration is probable. 



}. R. Rippetoe and L. E. Wise 2 ) have also been working at the estimation 

 of citral in oils of lemon. Their reason for taking up this investigation 

 was the desire to substitute another and more reliable method for that 

 of Sadtler (comp. Report April 1904, 48 and October 1904, 119) which has 

 been incorporated in the U. S. Pharmacopoeia. With this object in view 

 they submitted the methods worked out by Chace and Hiltner to control- 

 tests, and they came to the conclusion that Hiltner's method might possibly 

 be suitable for admission into the Pharmacopoeia. In that case, of course, 

 the minimum-content of citral demanded by the Pharmacopoeia would 

 need to be reduced from 4 to about 3,8%.. 



Parry 3 ) reports on several shipments of lemon oil adulterated with 

 turpentine oil. The oils in question were distinguished by their abnormally 

 low optical rotation (+50 to +54°), and also attracted Parry's attention 

 because their citral value was very low (3,3 to 4,1 %). Closer examination 

 revealed the presence of copious quantities of pinene, pointing to sophistic- 

 ation with turpentine oil. The comparatively ™small drop in optical rotation 

 considering the amount of adulterant present leads Parry to think that in 

 every case the adulterant was Greek turpentine oil, wich has a high dextro- 

 rotation, and he was confirmed in this view by hearing from Sicily that 

 Greek turpentine oil is used there as an adulterant of lemon oil. 



Orange Oil. According to Brooks 4 ) it would be possible to prepare 

 in the Philippine Islands from the peel of the fruit of Citrus reticulata,. 

 Blanco, known locally as naranjita, an oil which is almost identical with 

 Italian orange oil. Citrus reticulata is generally regarded as being synonymous 

 with C. Aurantium, L, but Brooks is of opinion that this is not correct. 

 The oil, which was pressed from the green peel, had the following constants: 

 a D3oo 90,85° (+?), n D30O 1,4700, ester v. 8,0, residue of evaporation 2,25 

 to 2,4%. It contained about 92% limonene, about 0,3% of a wax-like 

 stearoptene, m. p. 116 to 117°, 0,5% of an acid (possibly butyric or caprylic 

 acid), and traces of a phenol. 



Another Citrus-species which is cultivated in the Philippines is Citrwz 

 Aurantium, Blanco, the fruit of which is locally known as cajel This fruit 



x ) Hiltner now uses for purposes of estimation 5 g. oil. U. S. Dep. of Agriculture, Bureau; 

 of Chemistry. Bulletin No. 137 (20. VII. 1911), p. 72. 



2 ) Americ. Journ. Pharm. 83 (1911), 558. 



3 ) Perfum. and Essent. Oil Record 2 (1911), 209. 

 . 4 ) Philippine Journ. of Sc. 6, A. (1911), 345. 



