V.— CHEMISTEY AND PHYSICS. 



Art. XLVI. — Studies on the Chemistry of the Neiv Zealand 



Flora. 



By T. H. Easterpield, Professor of Chemistry, Victoria 

 College, and B. C. Aston, Chemist to the Agricultural 

 Department. 



[Read before the Wellington I'liilosophical Society, 5th November, 1901.] 



PART II.— THE KABAKA-NUT. 

 (Preliminary Note.) 



The karaka-tree (Corynocarpus Icevigata) is endemic to New 

 Zealand and the surrounding islands. It is plentiful in the 

 North Island, but its distribution in the South Island is very 

 limited. It is the largest and commonest of all the trees in 

 the Chatham Islands, where it attains a height of over 50 ft. 



The kernel of the karaka-berry is known to be very poison- 

 ous in its raw state, but if suitably prepared by cooking and 

 subsequent soaking the kernel forms a staple article of 

 xMaori food. A detailed account of the process as carried out 

 by the Maoris is given in a paper by Skey.* Owing to the 

 kindness of Mr. H. B. Kirk, Inspector of Native Schools, we 

 have been informed that the process employed by the 

 Morioris in the Chatham Islands is practically identical with 

 that used by the Maoris. 



The karaka-kernels have been investigated by Skey. The 

 results of his examination showed — (1) That the kernels con- 

 tain oil, sugary matter, gum, and amorphous proteids ; (2) that 

 the nuts lose their bitter taste when heated to 100° C. for four 

 hours ; (3) that animal charcoal removes from the acidified 

 aqueous extract of the kernel a bitter crystalline substance. 

 This compound was named "karakin," but was not obtained 

 in sufficient quantity for a satisfactory examination. 



The authors have re-examined the karaka-nut. They find 

 — (1.) That the aqueous extract of the nut yields much 

 prussic acid on distillation. (2.) That air-dried kernels contain 

 14-15 per cent, of non-drying oil, which yields solid acids on 

 saponification. (3.) That the sugars present are mannose and 

 dextrose. (4.) That the aqueous extract, upon evaporation, 

 even at 35°, in shallow pans, loses the greater part of its 

 bitter taste. The concentrated extract contains no karakin 



* Trans. N.Z. Inst,, vol. iv., p. 318. 



