— 146 — 



with petroleum ether boiling at a low temperature, and distillation of 

 the latter in in vacuo yielded a gum- like extract of pleasant odour. 

 Better results were obtained by maceration ("enfleurage") with paraf- 

 fin oil. 



The last report of Roure-Bertrand Fils l ) also contains information 

 concerning Plumiera acutifolia Poir., together with a coloured illustration 

 of the flower. 



While in the preparation of chemical compounds recourse is very 

 often had to high temperatures, in the case of plants even the most 

 intricate chemical processes are accomplished at low temperatures, but 

 at high pressure, i. e., the osmotic pressure present in plants. In the 

 opinion of G. Austerweil 2 ), the importance of this factor has been 

 too much neglected in our chemical operations The researches of 

 Barbier have shown that pressure is also a factor in the conversion 

 of members of the terpene series, Barbier having demonstrated 

 that linalool, when heited with acetic acid in an autoclave at 160 

 to 170 , is converted into geraniol 3 ). In the author's view this 

 process also takes place in the vegetable Kingdom. Austerweil, referring 

 to Pfeffer's opinion that osmotic pressure is greater at the equator 

 than at higher latitudes, records as in harmony with this view the 

 fact that an oil of petitgrain which had been distilled at 44°45' N. Lat. 

 was poorer in geraniol (1 part geraniol to 5 parts linalool) than an oil 

 distilled from plants grown at 20 S. Lat. in South America, the latter, 

 according to Umney and Bennett 4 ), containing 38% geraniol and 

 30% linalool. 



We should like to add to this example the following footnote: 

 As for the figures quoted, they can only be approximate, inasmuch 

 as no exact method for separating linalool and geraniol is known. 

 Further, the figures given by Umney and Bennett and cited by Auster- 

 weil refer, it is true, to a South American oil, but it was not specially 

 stated that this oil was distilled at 20 Lat. But in the same table 

 the composition of Paraguay petitgrain oil is given as i8,9°/ geraniol 

 and 52,4 °/o Hnalyl acetate! In further support of his theory, Austerweil 

 adduces oil ot lavender (erroneously calling the parent plant Lavandula 

 Stoechas instead of L. vera D. C), and maintains that English lavender 

 oil from herb grown at 55 N. Lat. does not contain geraniol, while 

 this substance is found in French oil from plants growing in about 

 45 N. Lat. In criticism of this statement we may say that no exact 



x ) Berichte of Roure-Bertand Fils, April 1909, 33. 



2 ) Compt. rend. 148 (1909), 1 197. 



3 ) We may observe that to accomplish this, no pressure at all is required, 

 and that this conversion takes places when linalool is boiled with acetic acid. 



4 ) Pharmaceutical Journal 72 (1904), 217; Report April 1904, 74. 



