94 PROCEEDINGS OF SECTION B. 



gelatinize. The dry kino is friable and does not deteriorate if kept 

 dry. A tincture made 16 years ago from the kino of this species is 

 in the Technological Museum, and is now as fluid as it was at first. 

 The exudation of E. microcorys would be the best for tinctures, but 

 unfortunately this species yields kino too sparingly for it to be of much 

 commercial value. E. calophylla yields kino in abundance, so that 

 it should be profitable to collect. It is highly astringent, is readily 

 soluble in alcohol, does not require glycerol, and on the addition of 

 water does not form a precipitate. It is thus a superior material for 

 tinctures to that at present in use by pharmacists for this purpose. 



The tincture made from the kino of E. maculata, and one or two 

 others, become turbid on the addition of water. 



The rapidity of gelatinization of eucalyptus kinos may be quickly 

 determined by adding 15 drops of formalin to 5 c.o. of the tincture, 

 B.P. strength. Kinos belonging to Class I, generally form jellies 

 in 24 hours ; those of Class II. and the intermediate section mostly 

 under a week ; while the most resistent of those of Class III. do not 

 form jellies. Kinos of Class IV. are largely insoluble in alcohol, but 

 if first dissolved in water and alcohol added in quantity insufficient 

 to cause precipitation, they readily gelatinize by the formalin test. 



In a paper on eucalyptus kinos and their value for tinctures, 

 Proc. Roy. Soc, N.S.W., 1904, p. 102, a table is given showing the 

 rate of gelatinization of the kinos of several eucalyptus species, deter- 

 mined by the formalin test. It is there shown that six months was 

 not sufficient to cause gelatinization in the tinctures of E. calophylla, 

 E, microcorys, E. eximia, and E. maculata, although those of some 

 species formed jellies in 24 hours. The specimens prepared for that 

 paper have been preserved, and to-day, nine years afterwards, the 

 tinctures of the four kinos above enumerated are still quite fluid. No 

 stronger confirmation of the non-gelatinization of the kinos of this 

 small group of eucalypts could be advanced, and pharmacists need 

 not be troubled with gelatinized tincture of kino. If the kino of E. 

 calophylla could be collected at about 15 to 18 pounds (sterling) per 

 ton, it might be profitably used directly for taiming purposes considered 

 as a natural tannin extract, although it would give a dark-red coloured 

 leather. Some attention has, in the past, been given to this question, 

 but apparently not systematically, and we know little about the best 

 methods for its production, or the time of the year most suitable for 

 its collection. The exudations belonging to Class IV., although so 

 plentifully distributed in the barks of certain species, E. crebra and 

 E. sideroxylon for instance, are very sluggish, and combine with exceeding 

 slowness with hide substance, although precipitated by gelatine. A 

 method whereby this difficulty might be overcome and the kinos thus 

 rendered more suitable for tanning purposes than they are in their 

 natural condition is a desideratum, and a problem worthy of serious 



