318 Mary Davies Swartz, 



fibers, the carbohydrate was precipitated by pouring the thick sHmy 

 mass into about six times its volume of 95 per cent alcohol. After 

 standing some hours, a transparent, gelatinous precipitate settled to 

 the bottom, and was filtered off through several thicknesses of gauze. 

 Dehydrated by means of absolute alcohol and ether, it formed a gray- 

 ish-brown powder. This was found to be soluble in dilute alkali, and 

 was subsequently purified by dissolving in 1 per cent potassium hy- 

 droxide, filtering through cotton and reprecipitating with 95 per cent 

 alcohol. The product was somewhat lighter in color than at first, 

 but still far from white. It was soluble in hot Fehling's solution, but 

 precipitable with lead acetate. It gave no color with iodine, although 

 a small amount of starch was present in the original bark. 



Furfurol tests were faint showing only traces of pentosans, but the 

 yield of mucic acid was large, 0.15 grams of mucic acid being obtained 

 from ] gram of the air dry powder. 



The products of hydrolysis were dextro-rotatory and contained 

 no fermenting sugars. Hence this preparation consisted chiefly of 

 galactan. 



A MANNAN PREPARATION. 



Since none of the algae which form the basis of these studies yielded 

 mannan, save Limu Lipoa, and that in amounts inadequate for the 

 experiments proposed, this hemicellulose was obtained in soluble 

 form from salep. Both the small, horny dried tubers and the grayish- 

 white powder made from them,wer. purchased from Schieffelein& Co., 

 New York. 



A preparation of pure mannan was made in the following way: 

 The tubers were soaked in cold water 24 hours, washed thoroughly 

 and ground in a meat chopper. To this mass, cold water was added 

 in large volume, and the whole allowed to stand over night, then the 

 dissolved mannan filtered off through gauze. According to Hilger 

 (254), the extract made in this way should contain no starch. But 

 when the tubers are heated before drying, the starch is made soluble, 

 and in this instance the cold water extract gave a blue color with 

 iodine. 1 Hence subsequent extractions were made with hot water on 

 a water bath, for several hours. The salep swells very much in water 

 so that a very large portion was required to get the mannan all into 



'Salep tubers purchased since this work was done yielded only a trace of starch 



jn the cold water extract. 



