66 Appendix. 



This change was sometime since effected by Prof. Kolhe, 

 through the action of carbonic acid gas on phenol in presence of 

 sodium. Last year he gave preliminary notice of his present 

 method, in which soda at elevated temperatures takes the place of 

 metallic sodium, and early in the present year the manufacture of 

 salicylic acid from carbolic acid and sal soda by use of carbonic 

 acid gas commenced at Leipsic (**). 



It is singular that the reverse of this change, the manufacture 

 of pure carbolic acid from the salicylic acid of wintergreen oil, 

 was reported on by Broughton, the quinologist of the British 

 Government in India, in 1871, as possibly a remunerative enter- 

 prise, at least "in case of war " or other occasion of increase in 

 the English price. The oil was obtained from the Andromeda 

 Leschenaultii, which grows in great abundance on the Neilgherry 

 Hills C 25 ). 



These few instances of artificial synthesis in the aromatic 

 group have acquired prominence on account of their relations to 

 wealth and industry; but instances of almost equal scientific im- 

 portance are thickly spread among the reports of every month. 



The natural production of aromatic bodies does not wholly 

 elude chemical investigation. Some of the chemical changes in 

 the aromatic constituents of the balsams are striking illustrations 

 of the well known characteristics of these bodies. Resins are 

 produced from the terpene and cymene oils by atmospheric oxi- 

 dation; and benzoic and cinnamic acids are produced from the 

 aldehyde, alcohol, and ether of the cinnamic series, by oxida- 

 tion ; and without doubt these oxidations occur within coniferous 

 trees, as well as more generally after exudation from the bark, 

 and in the same way in the bottle on the shelf where light falls. 

 As changes of oxidation, these are not representative of the 

 vegetable kingdom; nevertheless they are in the direction of 

 greater complexity of chemical structure. 



(24) KOL.BE: J.pr. Ch. [2] viii, 41; in Jour. Chem. tfoc., 1874, 373. 



(25) Phar. Jour, and Trans. Oct. 7, 1871. 



