Nutrition Investigations. 



317 



Kohu preparation should have been dried in ■vacuo, for it proved to 

 be slightly hydroscopic, and instead of remaining a fine white powder, 

 became somewhat brownish. The Uaualoli preparation dried easily 

 to a grayish white, light, fibrous mass. 



Tests for starch and reducing sugar were negative on all these 

 substances. Tests for galactans and pentosans were positive in every 

 case. Three-gram samples of the air-dry preparations of Limu 

 Akiaki, Limu Uaualoli and Limu Kohu respectively yielded 0.53 

 grams, 0.92 grams and 0.64 grams of mucic acid, recrystallized once 

 from ammonium carbonate.^ The products of hydrolysis in no case 

 contained fermenting sugars. It is evident therefore, that these five 

 preparations from the foregoing Hawaiian seaweeds consisted chiefly 

 of galactans, accompanied by some pentosan-groups. From the 

 frequency with which methyl-pentosans have been shown to occur 

 in all seaweeds previously investigated, it is very likely that they 

 occur in all these varieties and it would be desirable to make tests for 

 methyl-pentosans. 



Determinations of the reducing power were made, as shown in the 

 following table: 



Slippery Elm. For the preparation of the carbohydrate which 

 forms the mucilaginous extract of slippery elm bark, pieces of the 

 latter were torn into narrow strips and allowed to stand over night 

 in cold water,- and then the mucilage expressed by squeezing through 

 gauze. This process was repeated until the bark became a mass of 

 separate fibers. The mucilaginous principle swells in cold water to 

 a transparent jelly, but is soluble only to a very limited extent. It 

 was found impossible to filter it, even through gauze, and therefore, 

 although it contained small particles from the disintegrated bark 



^For method cf. Bull. No. 107, p. 55, Bureau of Chemistry, United States 

 Dept. of Agriculture. 



- It was found impossible to extract the mucilaginous principle in hot water. 



