98 



ON THE OCCURRENCE OF MUCIN IN PLANTS. 



Composition of the yam. 1 ) 



Water 



80.74 



In 100 parts of dry matter, 

 Crude protein 



11.74 

 0.84 



4-36 

 3.60 

 22.13 



57-33 

 1.879 

 0.675 



Fat 

 Fibre 



Ash (free from Co,) 

 Starch 



Other non-nitrogenous substances. 

 Total nitrogen 

 Nitrogen in amides, etc. 



2 Preparation of the Slime of Yams- 



The slimy matter forms a thick turbid liquid and can 

 be easily freed from starch granules and other substances by 

 simply filtering. The filtered liquid shows a neutral reaction, 

 and is precipitated by the addition of acids, but the pre- 

 cipitation is prevented to a certain extent by the presence of 

 common salt. Several methods are proposed for the isolation of 

 mucin. 



Landwehr*) prepared the mucin of the bile by precipitating 

 with acetic acid, washing, dissolving in 1% solution of soda, 

 and precipitating again. Obolenski 3) recommended a method of 

 purifying the mucin of the submaxillary glands as follows : The 

 glands are soaked in water over a night and filtered. The filtrate 

 is precipitated with acetic acid, the precipitate washed first 

 with water and a little acetic acid, then with hot alcohol and 

 finally dried. But Hammarstcn 0 recommended a new method 

 which is well adapted to separate mucin from substances belong- 

 ing to the group of nucleoalbumins. The mucin of the sub- 

 maxillary glands is soluble in dilute hydrochloric acid (0.1 — 

 0.2%) and is precipitated unchanged by adding 3 or 4 times 

 its volume of water to the solution, while the nucleoalbumin 

 dissolves in dilute hydrochloric acid together with the mucin, 



1) The analysis was made in the agricultural chemical laboratory of the Im- 

 perial College of Agriculture in Tokyo. See Bull. Vol. I. 



2) Z. physiol. Chem. Bd. V, 371. 



3) Pfliig. Arch. 4. 



4) Z. physiol. Chem. Bd. XII. 



