182 J. H. MAIDEN. 



in any case to correspond in quantity with their intense astringent 

 taste; and occasionally the addition of that substance causes no- 

 precipitate at all. This fact has an important bearing upon the 

 value of this whole class of bodies under consideration for tanning 

 purposes, and as substitutes for catechu and similar bodies. 



"With acetate of lead these astringent bodies give copious 

 gelatinous precipitates, and with the salts of iron various shades 

 of green and black. The mineral acids also determine in them 

 bulky flocculent precipitates." . . . "The solvent action of 

 water on these bodies is not the same in the case of gums from 

 different species of trees. If for instance cold water is poured on 

 the produce of E. corymbosa, whether it be in the solid or liquid 

 state, a portion only is taken up, while the gum from the stringy- 

 bark is completely dissolved. When as in the case just cited, a 

 flocculent residue remains after the action of water, a few drops 

 of ammonia render the solution perfect." 



By far the fullest experiments on Eucalyptus kinos hitherto 

 made are those of Prof. Wiesner of Vienna, published in the 

 Zeitschr. d allg. oesterr. Apotheher-Vereines. (Wien, 1871). 

 JPharm Journ. [3] ii. 102. Following is a brief extract: — 



"These samples show a pretty uniform reaction; they all give 

 with sulphuric acid a pale-red, flocculent precipitate; the aqueous 

 solution always 1 gave with perchloride of iron a dirty green pre- 

 cipitate, with the exception of E. obliqua, which gave a dark violet 

 coloration. . . . Well known authorities in pharmacognosy 

 have been inclined to doubt the kino-like character and to look 

 upon it merely as a gum-resin impregnated with colouring matter. 

 It therefore became necessary to determine the constituents of 

 Eucalyptus gum; and the author finds the principal part of all 

 samples to be nothing but so-called kino-tannic acid. He obtained 

 by Berzelius' method a red, amorphous substance identical in all 

 its reactions with kino-tannic acid. 



1 The following being among the species examined by Prof. Wiesner, 

 E. amygdalina, piperita, leucoxylon, pilularis, together with varieties of 

 amygdalina, these generalizations will not hold good. The italics are mine. 



