Nutrition Investigations. 315 



This was considered sufl&ciently pure for feeding experiments, and was 

 quickly dried by pouring into broad shallow dishes and placing over a 

 steam radiator. It formed yellowish, translucent scales, which were 

 easily removed, and finely groimd. 



Subsequent extractions were made in a steam sterilizer, heating 

 several hours at a time. Tests showed that the carbohydrate was 

 not hydrolyzed by this repeated subjection to high temperature. 

 The several extracts were first strained off through gauze and 

 then filtered hot through cotton, to remove the cellulose 

 particles. As these clogged even cotton filters very rapidly, it 

 was found most satisfactory to let the extracts stand over night, 

 decant off the supernatant fluid as far as possible, and filter 

 in a water-jacketed funnel. Solutions containing over 1 per cent 

 dry substance could not be filtered through paper. For experi- 

 ments where a perfectly clear fluid was desired, a \ per cent 

 solution was filtered hot through plaited paper, and then concentrated 

 on a water bath to the desired strength. One per cent solutions 

 formed a soft jelly on cooling; 2 per cent solutions, a firm jelly. 



Even when evaporated to a thick syrup, the carbohydrates of the 

 Irish moss extract are not readily precipitated by comparatively large 

 volumes of 95 per cent alcohol, but form a voluminous, transparent, 

 gelatinous mass. This was found to be more or less characteristic of 

 all the galactans examined. They could be brought down most 

 satisfactorily by addition of sodium chloride to the extract before 

 pouring it into the alcohol. In this way a white precipitate of fine 

 fibers was obtained from the moss. The carbohydrate could also 

 be precipitated by saturation with potassium acetate, and freed from 

 inorganic salts by dialysis, according to the method described by 

 Pohl (263). It could not be precipitated by FehHng's solution, nor 

 by lead acetate in neutral solution. 



Owing to the opacity of its solutions, and to the fact that its gelat- 

 inizing property made the use of very dilute solutions necessary, no 

 satisfactory determination of its specific rotation could be obtained. 

 A 0.5 per cent solution, clarified with alumina cream, and examined in 

 a 200 mm. tube, showed a rotation of -f 0.34°, and other trials gave 

 positive evidence that it was dextro-rotatory. The products of hydro- 

 lysis were also dextro-rotatory, and yielded osazones, which after one 

 recrystalUzation from alcohol, had a melting point of 184°-185° C. 



The carbohydrate gave a red- violet color with iodine, and con- 

 tained no reducing sugar. A faint furfurol test was obtained. Oxi- 

 dation with nitric acid gave a rich yield of mucic acid. Since Hadike, 



