332 



vinegar. It is a white crystalline mass, melts at 112° C, and 

 volatilises even at lower temperatures. It lias a bitter taste, hut 

 is scarcely of acid reaction. In contact with hydrochloric acid it 

 tinges fir-woods violet; it dissolves in water, alcohol, and ether. 

 The aqueous solution deposits a white precipitate with lead-acetate, 

 and colours ferric salts dark-gi"een; nitric acid decomposes it into 

 oxalic acid and a small portion of a yellow nitro-compound 

 (Watts). For its direct occurrence in plants see page 182. 



Tannic Acid (its estimation). — Exhaust with boiling water, 

 filter, add a solution of chi*ome-alum as long as a sediment is 

 formed, filter after a few hours, wash out, dry at 100° C, and 

 weigh; then incinei^ate the dry precipitate and weigh again the 

 remaining oxyd of chromium ; the first weight minus the latter 

 one gives the amount of tannic acid. — (F. v. Mueller and L. Rum- 

 mel). The active tannic principle in oak-bark seems as yet 

 not strictly chemically defined. 



P. 269, add, before Coniferse: 3, Gymnospermce. 



Many substances, of which as yet the chemical formula has 

 not been carefully ascertained, or of which well-marked charac- 

 teristics are not yet on recoi'd (such as Podophyllum-resin, oil of 

 Erigeron Canadensis, &c.), are omitted in this work for the present. 



P. 40, 1. 18. — Instead of Fibrwi read Fibre. 



P. 68, 1. 11.— Strike out "alkaloid." 



P. 91, 1. 20, 21, 25, 27.— Instead of "Gin^Äoic, Gin^Ä;o, 



Gin^^-oate" read " Ginkgoic, Ginkgo, Ginkgoate." 



P. 149, 1. 14. — Instead of "Eucalyptm" read "Eucalypten." 



P. 171, 1. 29. — Instead of Pholobaphen read Phlobaphen. 



P. 174, 1. 11. — Instead of "cerop?'c" read " ceropinic." 



P. 226, 1. 13. — Instead of "acids" read "acrids." 



P. 229, 1. 2.— Instead of "C23 H26 N2 O4" read "CieHoe N2 Og/' 



P. 231, 1. 10.— Instead of "C22 H23 NOg" read C44 H23 NOie." 



p. 272. — Eead Hule-Caoutchouc instead of Ule Caoutchouc. 



M'Carron, Bird & Co., Printers, 37 Flinders Lane West, Melbourne. 



