MANNAN CONTENT OF THE GYMNOSPERMS 199 



purities, dried and weighed. The mannan content was calculated from 

 the weight of the mannose phenylhydrazone by multiplying by the 

 factor 0.6. The yields are based on dry wood, the moisture having 

 been determined in an air oven at 105 degrees. 



The cream-colored mannose hydrazone was dissolved in hot 75 

 per cent alcohol and filtered, using a suction pump. The filtrate usually 

 l)ecomes opaque at once from the separation of microcrystals of the 

 hydrazone. Three crystallizations usually gave practically colorless 

 crystals. The melting point of the various hydrazones varied from 188 

 to 190 degrees by slow heating. 



The results obtained are given in Table 1. The wood in all cases 

 was taken from the trunk of the tree and unless otherwise stated the 

 sample represents a radical section containing both heartwood and 

 sapwood. The sample descriptions, where possible, are given in some 

 detail, since future work may show that the mannan content is de- 

 pendent on such factors as the age of the tree, season and locality. 



Duplicate determinations of the mannan content usually did not 

 dififer more than 0.3 to 0.4 per cent, but occasionally differences as high 

 as 1 per cent were observed. To determine if all the mannan had 

 been- hydrolyzed the sawdust from limber pine heartwood and long- 

 leaf pine sapwood was air-dried after the first hydrolysis. This was 

 again boiled with fresh acid and treated in the customary manner. 

 Since the alundum crucibles increased in weight but 0.003 and 0.00-4 

 g. respectively, there was practically a quantitative removal of the 

 mannan in one hydrolysis. 



Table 1. — -Mannan Content of Various Conifers 



No. 



Species 



Mannan Description 



6.57 

 5.13 

 1.44 



Cut in May; Washington. 



May: 4 ft. up; 6 in. diameter. 



Arizona. 

 Montana. 



Wisconsin. 



! Per cent 

 Douglas fir {Pseudotsuga taxi- ! 6.65 



folia Briton) 

 Corkbark fir {Ahies arizonica 



Merr.) 

 Western larch (Larix occiden- 



talis Nutt.) 

 Arborbitae {Thuja occidentaUs 



White spruce {Picea canadensis 



Mill.) 

 Longleaf pine {Pin us palustris 



Mill.) j 



Longleaf pine {Pinus palustris 1.64 July; sapling 6 yrs. old; 1.5 ft 



Mill.) { up; 2 in. diam.; Mississippi. 



Loblolly pine {Pinus taeda 5.10 I May; Florida. 



Linn.) 



7.12 I November; 12 ft. up; 13 in. 



diameter. Wisconsin. 



4.75 'May. Florida. 



" Extracted with hot water to remove galactan previous to hydrolysis. 



