Scientific and other notes on essential oils. 29 



Hood is of opinion that lemongrass oil ought to be judged by its citral content 

 and not according to its solubility. 



We cannot agree with him in taking no notice of the solubility, but demand now 

 as ever that, in addition to a certain proportion of citral, a good lemongrass oil must 

 show a sufficient solubility in alcohol. Bad solubility indicates the presence of resinified 

 constituents or of unsoluble hydrocarbons, which make the oil useless for certain 

 purposes. As a matter of fact, all attempts of introducing the sparingly soluble oils 

 in commerce have failed, so far. According to the latest investigations, it seems to 

 be pretty sure that the sparingly soluble, so-called West-Indian, lemongrass oil from 

 €ymbopogon citratus contains myrcene, which is known to be sparingly soluble and 

 which, above all, has a strong tendency to form insoluble polymerization products. 

 The results of Hood's experiments indicate that exhaustive distillation of lemongrass 

 leads to oils with high citral content and which are readily soluble in the beginning.' 



The oils obtained in Florida were all well soluble at first, but after three months' 

 storage they had lost their ready solubility. 



Unfortunately, Hood does not give any further details as to the physical qualities 

 of the Florida oils. 



The costs per acre are as follows: — 



first year: following years: 



preparing the soil 3 dollars 



planting . . 2 „ 



manure . 8 „ manure 8 dollars 



labour 2 „ labour . . 1 „ 



cutting and distillation .... 5 „ cutting and distillation .... 8 „ 



together 20 dollars together 17 dollars 



J first year — 25 lbs. of oil at 80 cents = 20 dollars; 



\ following years = 35 lbs. of oil at 80 cents = 28 dollars. 



Several small items not having been taken into consideration, it is questionable 

 whether lemongrass growing by itself will pay. Hood advises, in consequence, to 

 carry it on in connection with other aromatical plants. 



On page 29 of our April Report 1915 we discussed the occurrence of a white and 

 of a red-stemmed variety of lemongrass, observed in Madras. The distillates from 

 both varieties were duly described by the London Imperial Institute. The oil from the 

 white-stalked grass reminded as well by its smell as by its other qualities more of 

 citronella oil than of lemongrass oil. Recently its botanical examination cleared up 1 ) 

 the question of the origin of the mother-plant, which we identified as Cymbopogon 

 flexuosus, Stapf /. albescens, a colour variety of the common lemongrass. The oil 

 obtained on this occasion showed the following characteristics: d i5 o 0.915; insoluble in 

 5 vols, of 70 per cent, alcohol at 15°; soluble in 2.5 vols, of 70 per cent, alcohol at 20°; 

 soluble in 0.7 and more vols, of 80 per cent, alcohol. The aldehyde content amounted 

 to 81.0 per cent. 



Hence it appears that the oil and its aldehyde content is normal, whereas the 

 oil formerly described only contained 9 per cent, of aldehydes and gave the following 

 data: di 5 o 0.909; « D — 10° 50'; soluble in 0.8 vols, and more of 80 percent, alcohol; 

 insoluble in 70 per cent, alcohol. How the bad solubility of the oil could be explained 



l ) Bull. Imp. Inst. 14 (1916), 381. 



