ON KAKI-SHIBU, A FRUIT JUICE IN JAPAN. 



333 



and 0.358 g. or 99.3% of organic matter. This film turns black 

 with ferric chloride. 1 



When Kaki-shibu is mixed with an equal volume of alcohol 

 no precipitate is observed, but on a further addition of alcohol 

 and some ether an almost white flocculent precipitate was 

 formed and this on standing gradually turned reddish brown. 

 Very remarkable is the behaviour towards acids. A moderate 

 quantity of mineral acids will give no precipitate ; while on 

 further addition much precipitate is produced, 3 which is again 

 soluble in pure water and alcohol, and very easily in dilute 

 acids. Of organic acids a larger quantity is required than of the 

 mineral acids. 10 c.c. of old Kaki-shibu requires nearly 15 c.c. 

 of concentrated sulphuric acid to produce complete precipitation. 

 In this behaviour towards acids the tannin compound is like 

 ordinary tannins, although in some other respects its behaviour 

 is quite different. 



I have carried out the tannin determination by the Lcewen- 

 thal method as improved by von Schroder, and have found the 

 results calculated as both gallotannic acid and quercitannic 

 acid; they were respectively 4.883 g. and 5.041 g. in 100 c.c. of 

 the new Kaki-shibu ; and 3.535 g. and 3.649 g. in 100 c.c. of the 

 old. The former correspond respectively to 74.7% and 77.1% 

 of its total solid matter ; while the latter had 58.7,% and 60.6%. 



The commercial Kaki-shibu neither contains sugar, nor does 

 it yield sugar on decomposition with sulphuric acid. The Kak; 

 tannin, therefore, is no glucoside. These reactions for reducing 

 sugar were always made after the tannin had been removed 

 with basic lead acetate. In one experiment 500 c.c. of commer- 

 cial Kaki-shibu were boiled on the addition of 15 c c. of concen- 

 trated sulphuric acid for three hours, and thereby a red precipitate 

 was separated on cooling in the form of little globules. This 

 precipitate, which increases on standing for twenty-four hours, 

 was then collected on a filter and washed with water for a short 

 time, since prolonged washing dissolved gradually a portion of it. 

 This precipitate resembling oak-red (Eichenroth), was colored 



1 It may be mentioned that the freshly cut surface of the unripe Kaki fruit when 

 moistened with ferric chloride gives no uniform black reaction, but merely in numerous 

 isolated points, and it seems therefore that the tannin is limited to certain cells. 



2 The fresh Kaki juice behaves differently, since it gives no precipitate with an excess 

 of acids. 



