312 Mary Davies Swartz, 



The products of hydrolysis were tested for fermenting sugar, with 

 negative results, but after heating with phenyl-hydrazin-hydrochloride 

 and sodium acetate, an abundant yield of osazones was obtained. 

 These crystallized out only on cooling, were pale yellow, soluble in 

 hot water only with great difEculty, but very soluble in alcohol, 

 acetone, or pyridin. After four or five recrystallizations from alcohol, 

 they melted at 152° C. and this melting point remained constant after 

 ten or twelve recrystallizations. However, there were very minute 

 points at which melting seemed to occur about 140° C. Under the 

 microscope, clusters of long needles were seen, each with a tuft of 

 small fine needles springing from its very tip. Dissolved in glacial 

 acetic acid, and examined in a 100 mm. tube, these osazones showed 

 no rotation of polarized light. 



A very white sample of the dulse carbohydrate was used to deter- 

 mine its specific rotation. It contained 7.1 per cent moisture and 

 1.68 per cent ash. Two determinations were made, one on a 0.6 per 

 cent solution and the other on a 1.0 per cent solution for which the 

 polariscope readings in a 200 mm. tube were respectively —0.90° 

 and —1.52°. The specific rotation, calculated from these readings 

 was therefore [ajn = —75.2° and —76.2°, or corrected for moisture 

 and ash, [a\^ = —82.4° and —83.6°, average, —83°. 



The rate of hydrolysis and maximum reducing power were deter- 

 mined as follows: 5 grams of the material dissolved in 500 cc. of 2 

 per cent hydrochloric acid were boiled in the usual way. At the end 

 of two hours, and at intervals of one hour thereafter, 50 cc. portions 

 were removed, neutralized and made up to 100 cc, and the amount 

 of reducing sugar present determined as dextrose. The following 

 results were obtained: 



TIME OF BOILING. SUGAR AS DEXTROSE. 



Hours. Per cent. 



2 87.2 



3 87.2 



4 89.4 



5 ■ 89.5 



That the results vary greatly with the concentration, is shown by 

 the fact that a 0.3 per cent solution boiled 5 hours yielded 67.1 per 

 cent of sugar as dextrose. 



Having established the fact that this dulse preparation consists of 

 pentosans, with the properties described, further investigations into 

 the exact chemical nature of the carbohydrates composing it were 

 not considered within the province of this work. 



