73 



have found the marmose in different plants. These investigators, 

 however, obtained it only by boiling different parts of the plants with 

 acids but they never found it in a natural state. Therefore, if it could 

 be proved that mannose is naturally found in this Araceous plant, it 

 would be indeed of very great interest. 



Firstly, I have examined with iodine solution under a microscope 

 small fragments of the leaf of this plant, collected in the afternoon 

 of a clear sunny day, and found that in the cells of the mesophyll and 

 in the ribs a very few granules coloured very faintly blue. Though 

 the cells of the leaf contained thus only a small amount of starch, 

 the cellular walls of the leaf gave the ordinary reaction of cellulose 

 with concentrated sulpharic acid and iodine. 



Further, I collected the leaf on a clear sunny afternoon, and 

 separated the petiole and the larger portion of the ribs from the blade 

 to which were however attached a few of the smaller ribs. Extracts 

 were made from both portions of the leaf with warm water at 40°-50° 

 and both extracts yielded a flocculent precipitate by mixing it with 

 several times the amount of strong alcohol. The resulting precipitate 

 was purified by redissolving in water, and was again precipitated with 

 alcohol. The aqueous solution of the precipitate being slimy, exhibited 

 the interesting property of loosing its slimy consistency on very prolonged 

 boiling, insoluble flocculi being separated out. The newly prepared 

 solution of the mucilage yielded a white flocculent precipitate with 

 basic lead acetate and ammonia, and a thick blue precipitate with 

 either Fehling's solution or copper sulphate and sodium hydrate. The 

 mucilage was boiled for about two hours with dilute sulphuric acid 

 of 3 o/ and after neutralizing the acid with barium carbonate, filtering 

 and evaporating, it yielded a sugar which gave at once the characteristic 

 precipitate of mannose-phenylhydrazon on the addition of phenyl- 

 hydrazine acetate. Thus, the mucilages from the petiole and blade 

 of the leaf agree in their essential properties with the soluble mannane 

 which Kinoshita found in the tuber. 13 It seems to me to be very certain 

 that all portions of the leaf of the plant contain the soluble mannane 

 like the tuber. 



The residue of the aqueous extraction of the leaf was boiled for 

 several hours with dilute sulphuric acid of 4% and the resulting syrup, 



Compare Kinoshita's article: Bui. Agr. Col. Imp. Univ., Vol. II., No. 4., p. 205—206. 



