liv GENERAL SUMMARY OF SCIENTIFIC AND 



tion of silver-dust upon bromacetic acid, a molecular con- 

 densation taking place. Erlenmeyer and Sigel have formed 

 a true nitrile of leucic acid by the union of hydrocyanic acid 

 and amyl-aldehyde; and from the nitrile they have obtained 

 the acid by simple oxidation. The mode of this synthesis 

 determines the true constitution of leucic acid. Pinner has 

 announced the discovery of a lactic acid belonging to the 

 allyl series, formed by boiling ethyl mono-chloracrylate with 

 barium hydrate. Kolbe has made the synthesis of salicylic 

 acid a commercial success. His method is to heat sodium- 

 phenol prepared by evaporating to dryness a saturated so- 

 lution of phenol in caustic soda first to 100, then to 180, 

 and finally to 220-250, a stream of dry carbonic gas being 

 passed continuously through the apparatus. A curious fact 

 observed at this time was that, while calcium and barium 

 hydrates also readily yield the salicylic acid, potassium hy- 

 drate thus treated yields an isomer of it para-oxybenzoic 

 acid. Some experiments, made for the purpose, proved the 

 remarkable antiseptic power of salicylic acid. 



Hofmann has examined the noticeable body discovered by 

 Liebermann in the crude wood-vinegar from beech-wood, and 

 termed by him coerulignon. The crude substance was the last 

 product of the distillation of beech-wood tar, and when treat- 

 ed with caustic soda solidified to a brown crystalline mass. 

 After purification, a colorless oil was obtained, which gave 

 on oxidation with chromic acid violet crystals agreeing in all 

 respects with coerulignon. Tiemann and Haarmann have 

 succeeded in producing the active principle of the vanilla 

 bean vanillin from a substance of entirely different origin, 

 viz., coniferin. The coniferin is extracted from the cambium 

 sap of several varieties of the pine-tree, and forms groups of 

 white needles in crystallizing. By the action of a ferment 

 emulsin, coniferin is split into dextrose, and a second prod- 

 uct which on oxidation with potassium dichromate and sul- 

 phuric acid yields vanillin. Steps have been taken to utilize 

 this discovery commercially. Fischer has investigated further 

 the remarkable body discovered by Baeyer, and called flu- 

 orescein. It is prepared by heating together two molecules 

 of resorcin and one of phthalic oxide to 200 ; and is ob- 

 tained as a crystalline red powder, non -volatile and quite 

 insoluble. It is especially characterized by the magnificent 



