— 55 — 



in order to produce again the same malformation in the following year. 

 Up to the present no practical remedy is known to protect the 

 peppermint plant from the attack of the eriophyes. 



In continuation of a previous communication 1 ) on Sicilian 

 peppermint oils, Umney and Bennett 2 ) report on a third oil of 

 the same origin, which had been distilled in July 1905. It agrees 

 completely in its properties with the oil distilled in July 1904: — 

 di5° 0,906; «d — 21 ; total menthol 4i,6°/ ; ester (menthyl acetate) 

 6,0 °/ ; free menthol 36,9°/ ; soluble in 3 volumes 70 per cent, alcohol. 



Petitgrain Oils. Whilst the real petitgrain oil, the essential oil 

 from the leaves and twig-ends of the bitter orange {Citrus bigaradia 

 Risso) has already repeatedly been examined, the constituents of the 

 essential oil obtained from the leaves and twigs of the sweet orange 

 (Citrus aurantium Risso) are still unknown. An examination made by 

 G. Litterer 3 ) according to the usual methods, disclosed as principal 

 constituents citral, geraniol, camphene and limonene. The 

 constants of the oil were; di 5 o 0,8603, « D -f- 56°46 ; , n D20° M7 2 - 



The citral, representing 4°/ of the oil, was isolated by shaking 

 with sodium sulphite liquor. The semicarbazone melted at 163 , the 

 citryl naphthocinchoninic acid at 19 7 . The portion of the oil from 

 which the citral had been removed contained 4, 1 °/ ester, calculated 

 for C 10 H 17 O • COCH 3 . The acetylation showed a content of 19,7% 

 alcohols of the formula C 10 H 18 O. Of these, i2,7°/ combined with 

 phthalic acid (geraniol). After saponification of the portions separated 

 from the citral, they were fractionated, and in the terpene fractions 

 were detected, camphene by conversion into isoborneol, and limonene 

 by its tetrabromide (melting point 104 ). In the higher-boiling fractions 

 linalool was apparently also present, besides geraniol, but its presence 

 could not be proved owing to the small quantity. Geraniol was isol- 

 ated by means of the calcium chloride compound. 



An oil 4 ) produced by the same author 5 ) from the leaves and 

 twig-ends of the lemon tree {Citrus limonum Risso) had the specific 

 gravity 0,8824 at 15 ; a D -|- 2i°o8 / ; n D230 1,4725. From this oil 

 24°/ citral were isolated. The semicarbazone melted at 162 to 

 164 , the citryl naphthochinchoninic acid at 19 7 . 



x ) Report October 1905, 57. 



2 ) Pharmac. Journal 75 (1905), 860; Chemist and Druggist 67 (1905), 970. 



s ) Bull. Soc. Chim. III. 33 (1905), 1079. 



4 ) An oil of this kind has repeatedly been described by us. Citral had also 

 been detected by us already before. Comp. Report October 1896, 59; April 1902, 

 79: April 1905, 64. 



5 ) Bull. Soc. Chim. III. 33 (1905), 1081. 



