244 
K. OSIIIMA & T. TADOKORO. 
Mucins 15 are characterized as compounds of the protein molecule with a 
substance or substances containing a carbohydrate group. The carbohydrate 
has been identified with glucosamin (chitosamin) 25 . 
As the occurrence of mucin in the vegetable kingdom has not yet been 
fully 1 2 demonstrated, it seemed to us of great interest, to investigate whether or 
not the glucosamin group is present in the yam mucin and thereby elucidate 
its true nature. 
As the material of our study, the tubers of Dioscorea Batatas 
Dene, were taken and prepared in a manner essentially the same as that 
followed bv Ishii (1. e.), with but slight modifications as our experience 
suggested. The tubers were grated as thoroughly as possible and then allow- 
ed to stand for several hours when starch granules and other substances 
settled at the bottom of the vessel. 
The thick liquid thus obtained was strongly acid in reaction. It was 
filtered first through linen cloth, then through filter paper, without suction. 
The last precaution is neccessary, as otherwise some of the starch granules may 
pass through the filter. The starch was always tested with iodin solution 
under microscope. The starch-free filtrate was carefully acidified with dilute 
acetic acid until the concentration of the acid reached to 0.5-1% of the 
liquid, when a flocculent precipitate was formed in abundance. After stan- 
ding over night, the clear supernatant liquid was decanted, the precipitate 
transferred to a filter, and washed well first with 1% acetic acid, then with 
dilute hydrochloric acid to remove any adhering protein which might be 
soluble in it, then with a mixture of alcohol and ether and finally with ether 
alone. When dried in vacuum over sulphuric acid, a yellowish amorphous 
mass was obtained. About 4.5 grams of the preparation were thus procured 
1) Under mucins we include both true mucins and paramucins, the latter as distinguished 
from the former, chiefly in the property of not being precipitated form its solution by aeetic 
acid. Cf. R ö h m a n n Biochemie, Berlin, 1908, p. 702. 
2) Fr. Müller— Zs. f. Biol., 42 (1901), pp. 468—564. 
J. Seemann — Inaug. Diss. Marburg, 1898; Chem. Centr., 1898 II, p. 1271. 
C. Neu berg u. F. H e y m a n n-Beiträge z. chem. Physiol, u. Pathol., 2 (1902), p. 201. 
H. Steudel — Hoppe-Seylers Zs. physiol. Chem. Strassburg, 34 (1902), pp. 353 — 384. 
A. Oswald— Hoppe-Seylers Zs. physiol. Chem. Strassburg, 68 (1910), pp. 173 — 180. 
