202 JOURNAL OF FORESTRY 



According to Fischer^- when 0.1 g. of mannose hydrazone is dis- 

 solved in 1 c.c. of concentrated cold hydrochloric acid, -5 c.c. of water 

 immediately added, and the solution examined in the polariscope using 

 a 1 dcm. tube, the d-compound gives a rotation of 1.2° to the left. 

 The crude mannose phenylhydrazone obtained from Pinus lambertiana 

 was recrystallized three times from dilute alcohol. Two different 

 samples of the hydrazone purified in this way, using the proportions 

 given by Fischer, had the rotations — 0.657° and — 0.796°. Lindsey 

 and Tollens^^ found — 0.761° for the mannose hydrazone obtained from 

 sulphite liquor. 



A portion of the practically colorless hydrazone was heated with 

 phenylhydrazine acetate in aqueous solution for 1.5 hours on the steam 

 bath. The yellow osazone obtained, after recrystallization from 60 

 per cent alcohol, melted at 303-4°. 



A sugar solution obtained by the hydrolysis of white spruce was 

 treated with phenylhydrazine acetate in the. manner described above 

 and allowed to stand over night. The hydrazone obtained was so 

 very impure that a quantitative estimation of Aiannose was impossible. 

 The hydrazone was dissolved in 75 per cent alcohol, the solution 

 filtered, and allowed to crystallize. After these operations had been 

 repeated four times the crystals melted at 186-8°. 



It is proposed to extend this investigation to other species and de- 

 termine if the amount of mannan in a given tree actually varies 

 throughout the year. The statement of Czapek^* that mannans always 

 belong to the reserve hemicelluloses requires confirmation. It is very 

 questionable if the mannans, especially those occurring in the heart- 

 wood of trees, can be considered as reserve food materials. 



SUMMARY 



1. The results of the examination of 22 different species of Gymno- 

 sperms and 6 species of Angiosperms show that mannan is present in 

 appreciable quantities in all the conifers but is absent from the hard- 

 woods. 



2. It appears that the mannan content of the sapwood is generally 

 larger than that of the heartwood; mannan decreases from the base 

 upwards but remains uniform throughout the heartwood in a radial 

 direction. 



3. Mannan is of industrial importance in the production of ethyl 

 alcohol from sulphite liquor and by the hydrolysis of sawdust with 

 ratalyzers. 



i2Ber., 23 (1890), 384. 



13 Ann., 267 (1892). 350. 



" "Biochemic der Pflanzen" Zweite Auflage., 657. 



