VANILLA. 659 



liquid surrounding the seeds. It was formerly regarded as cinnamic or 

 benzoic acid, and then as cumarin, until Gobley (1858) demonstrated its 

 peculiar nature. 



The admirable researches of Tiemann and Haarmann performed in 

 Hofmann's laboratory at Berlin (1874-1876) have shown that vanillin 



is constituted according to the formula CH^-c OH , It is the alde- 



(CHO 

 hyde of methyl-protocatechuic acid, and like other aldehydes yields a 

 crystallized compound with the bisulphites of alkalis. This is obtained 

 by shaking an ethereal extract (e) of vanilla, with a saturated solution of 

 bisulphite of sodium. The vanillin compound remaining in aqueous 

 solution is mixed with sulphuric acid and ether; the latter on evapora- 

 tion affords crystals of vanillin. They melt at 81°, and may be sub- 

 limed by cautiously heating them. Vanillin is but sparingly soluble in 

 cold water, and requires about 11 parts of it at 100° C. for solution; it 

 strikes a fine dark violet with perchloride of iron. 



The said chemists have further demonstrated that vanillin may be 

 formed artificially. In the sapwood of pines there occurs a substance 

 called Coniferiv, Ci^^H^^'^Os + 2 H^O, first observed in 1861 by Hartig. 

 By means of emulsin coniferin taking up H-0, can be resolved into 

 sugar and another crystallizable substance:— C^'^H-O^ + WO = (yW^O^ 

 + C^^H'-'Ol The second substance thus derived may be collected by 

 means of ether, which dissolves neither coniferin nor sugar. By oxidiz- 

 ing it, or coniferin itself, by bichromate of potassium and sulphuric 

 acid, Vanillin is obtained. The latter has been for sometime manu- 

 factured in that way by Tiemann, but now eugenol (see p. 285) is used 

 for that purpose. Another source for vanillin is benzoin (p. 409). 



The amount of vanillin was stated by Haarmann and Tiemann to 

 be 1-69 per cent, in Mexican vanillin, from 19 to 2-48 in the Bourbon 

 variety, and 2*75 in that from Java. The so-called Vanillon afibrds 

 only 04 to 07 per cent, of vanillin. 



From the above-mentioned ethereal solution (e), after it has been 

 deprived of vanillin, vanillate of sodium may be removed by a dilute 

 solution of carbonate of sodium. On acidulating the aqueous solution 



rocff 



crystals of vanillic acid, C®H*-! OH are precipitated. If the ether of 



( COOH 

 the solution (e), after it has been treated with carbonate of sodium, is 

 allowed to evaporate, a mixture of fatty substances and a resin are 

 obtained. The latter has a peculiar odour, somewhat suggestive of 

 castoreum; vanillic acid is almost inodorous. 



Leutner (1872) also found in vanilla fatty and waxy matter 11*8, 

 resin 4 0, gum and sugar 16-5 per cent.; and obtained by incineration of 

 the drug 46 per cent, of ash. 



Production and Commerce — The chief seats of vanilla-production 

 in Mexico are the slopes of the Cordilleras, north-west of Vera Cruz, 

 the centre of the culture being Jicaltepec, in the vicinity of Nautla.^ 

 The finest specimens were contributed in 1878 to the Paris Exhibition 



^ Culture du vanillier au Mexique, in the W. von Miiller, Reisen in . . . Mexico, ii. 

 Heme Coloniale, ii. (1849) 383-390; also J. (Leipzig, 1864) 284-290. 



