BY R. T. BAKER. 389 



The Ijundles of root fibres run parallel to the outer edge of 

 the tuber, the distance between the respective bundles becoming 

 greater as the root expands in size, and contracting again at each 

 end. These root fibres account for the comparatively high per- 

 centage of crude fibre. The amount of mineral matter is also 

 large, and contains a large percentage of the chlorides; the other 

 constituents usually found in similar ashes were present as 

 phosphoric and sulphuric acids, lime, magnesia and the alkalies, 

 with a good percentage of potassium. 



Only a small quantity of starch is present, as only a few 

 granules were indicated by iodine. These granules are quite 

 spherical and vary much in size as ransrins: from -tt^tttt to o-^Vtt of 

 an inch, the largest number being about ywoct^^ an inch. Only 

 those granules stained blue were measured. 



A proximate determination of the constituents was not made 

 as the general value is so low. Although only 77 per cent, of 

 nitrogenous substances, calculated as albuminoids, was present, 

 yet it it is probable that even some of this nitrogen is not so 

 combined. Duplicate results were made. A fair section was 

 taken for analysis through the centre of a tuber and the mean 

 of the result stated. The results show that only 4^ per cent, of 

 carbonaceous principles is present — an exceedingly low result. 



The general constitution is as follows : — 



Water 90-774 per cent. 



Nitrogenous substance*' ... ... 0-770 ,, 



Starch and other carbonaceous prin- 

 ciples ... 4-564 ,, 



•Jrude fibre (ash free) 1-900 



Mineral matter! 1992 



100-000 

 I have to acknowledge my indebtedness to Mr. S. J. Johnston, 

 B.A., for the measurements of the starch granules, and also to 

 Mr. M. F. Connelly for the photographs illustrating this paper. 



* Equal to 0-123 per cent, nitrogen. 

 t Contains IS per cent, chlorine. 



