Commercial and scientific notes on essential oils. 7 



From 57 litres of the distillate (corresponding to 54 kg. of parings) they obtained 

 1.905 g. of an essential oil representing 0.0035 per cent, of the parings (0.0007 per cent, 

 of the whole fruit) in the following way: — The distillate was repeatedly submitted to 

 distillation in a current of steam until the volatile products had been concentrated in 

 8 litres of water. The oil was extracted from this liquid by means of ether. The oil 

 obtained was a yellow, somewhat viscous liquid which turned darker in the course of 

 time and smelt of fresh apples. Cooled a little below the ordinary temperature the 

 liquid changed into a soft mass. Some very tiny needle-shaped crystals segregated; 

 they were probably identical with the already-mentioned triacontane. Shaken with a 

 little water a few drops of the oil gave the acetaldehyde and furfural reactions. The 

 oil further contained the amyl esters of formic, acetic and caproic acids and a very 

 small quantity of the ester of caprylic acid. 



In the aqueous distillate from the Springdale apples the presence of small quantities 

 of methyl alcohol (according to von Fellenberg) 1 ) and of ethylalcohol (iodoform reaction) 

 could distinctly be established in addition to the already-mentioned compounds. It 

 could not be decided, however, whether the methyl alcohol was present as such in 

 the parings or perhaps as methyl ester of the pectin acid 2 ). 



The examination of the parings of the crab apples led to similar results. The 

 proportion of essential oil was somewhat higher and amounted to 0.0043 per cent, of 

 the parings, or to about 0.0013 per cent, of the whole fruit. 



Whilst in the first-studied species of apples the presence of acetaldehyde could 

 only be established by means of the reaction with dimethylamine and sodium nitro- 

 prusside, the authors were able to determine the aldehyde in the distillate of the crab 

 apples quantitatively as silver acetate by precipitating it by means of sodium bisulphite 

 and oxidising it to acetic acid. At the same time it was demonstrated that form- 

 aldehyde was absent, and that only traces of an apparently higher homologue were 

 present. The proportion of acetaldehyde amounted to about 0.001 per cent, of the 

 apple parings. 



So far it had been assumed that the lower aliphatic aldehydes were not present 

 as such in the plant, but were only formed during the distillation. Since now the 

 authors had in this case actually found relatively large proportions of acetaldehyde, 

 they further attempted to determine whether this aldehyde was present already in the 

 odoriferous constituents of the apples, or whether it was produced at a later stage. 



For this purpose 215 sound, red Nero apples (35.85 kilos) were put in a copper 

 boiler, provided with a tightly-fitting cover and with two small openings, above and 

 below. A current of air was drawn through the boiler, and this air had first been 

 purified with alkaline potassium permanganate solution and concentrated sulphuric acid 

 and had finally been passed through about 300 cc. of a saturated solution of sodium 

 bisulphite. The experiment lasted 7 or 8 days. At the end of this period the bisulphite 

 had bound a sufficient amount of acetaldehyde for definitely proving its presence by 

 means of ammoniacal solution of silver oxide, Schiff s reagent, and of dimethylamine 

 and sodium nitroprusside. Acetaldehyde is, therefore, a product of the living cell of 

 the fruit and is present as such in the odoriferous compounds of ripe apples. The 

 establishment of this fact is of importance for biologists. The growth of the scald, 

 which affects some apples when stored without sufficient circulation of air and which 

 is caused by a fungus (Fiisidadium pyrinum, Fuckel), may favourably be influenced, 

 for instance by the presence of acetaldehyde. 



') loe. cit. — 2 ) Cf. Tschirch, Arch, der Pharm. 252 (1914), 538. 



