100 ON THE OCCURRENCE OF MUCIN IN PLANTS. 



C 52,82 



H 7>53 



N 14,20 



O+S (calculated) 25,05 



Ashes 0,41. 



The determination of N was made after the method of 

 Kjcldahl. The substance contains sulphur. By boiling it with 

 caustic potash of 5%, the liquid became yellowish, and when 

 hydrochloric acid was added in excess, sulphuretted hydrogen 

 gas was evolved, and the paper moistened with lead acetate 

 turned black owing to the formation of lead sulphide. 



The composition of this slime is approximately the same 

 as that of the bile (see the following table). Identity is of 

 course doubtful, as there are many isomeric, especially stereo- 

 isomeric mucins, possible. 



C H N S O Ashes 



Mucin of tendon 1 .* 48.30 6.44 11-75 0.81 ■ ■ 



Mucin of submaxillary glands 2 ) 48.84 6.80 12.22 0.84 ■ 



Mucin of bile 3 ) 53-og 7-60 13.80 1.10 24.41 



Mucinous substance of yam roots 52.82 7.53 14.20 25.04 0.41 



Hammarsten declares : "Die Fahigkeit, beim Sieden mit 

 verdiinnten Sauren eine reducierende Substanz zu geben, die 

 physicalische zahe Beschaffenheit und das Verhalten zu Es- 

 sigsaure sind die drei wichtigsten Eigenschaften, welche die 

 Mucinstoffe in qualitative! - Hinsicht von dem Eiweissstoffen 

 unterscheiden." Our slime shows all the essential charac- 

 teristics of the animal mucin, and differs only in some sub- 

 ordinate points; it is with more difficulty soluble in dilute 

 alkalies and yields a turbidity with potassium ferrocyanide. 

 Our substance is doubtless a kind of mucin, and as this is 

 the first time that such a compound has been found in the 

 vegetable kingdom, it is certainly of physiological interest. 

 The quantily determined as accurately as possible, amounts 

 to 8% of the tuber dried at ioo°C. 



1) Locbisch, Ztschr. physiol. Chem. Bd. X, S. 61. 



2) Hammarsten, Ztschr. physiol. Chem. Bd. XII, 



3) Landwher, Ztschr. physiol. Chem. Bd. V, S. 371. 



