On the Occurrence of Mucin in Plants- 



BY 



J- Ishii, Nogakushi. 



In the animal as well as in the vegetable kingdom, there are 

 found substances of slimy nature, which serve for different 

 physiological functions ; but while the slimes of animals belong 

 to the protein compounds, all plant-slimes consist, so far as is 

 yet known, of carbohydrates, corresponding either to the formula 

 C 6 H IC 0 5 or C^H^Ou and yielding by hydrolysis different 

 kinds of sugar; as, for instance, carrageen or the slime of an alga 

 Chondrus crispus Lyngb) yields galactose (Hddicke, Bauer and 

 Toll ens), cerasin or the gum of the cherry-tree yields arabinose 

 (Scheibler, Kiliani), and the slime of beer-yeast yields mannose 

 (Hesscidand) . 



As a number of Japanese plants are so rich in slimy matters 

 as to be applied on account of this quality for industrial pur- 

 poses, I believed it to be, from a physiological as well as a technical 

 point of view, of some interest to investigate their proper chemical 

 relations. To my surprise I have found in the tuberous root of 

 yams a slimy matter that is precipitated from its solution by dilute 

 acetic acid. Further investigation has demonstrated beyond any 

 doubt, that this slime belongs to the class of mucins, and as this 

 remarkable occurrence is the first exception to a generally adopted 

 rule, I will describe in the following lines my observations in detail. 



1. Short Description of Japanese Yams. 



There are two kinds of yams growing in this country, the 

 one is called " yamano-imo" (Dioscorea japonica, Humb.) while the 

 other is called "finenjo" (Dioscorea batatas, Decaigne.) Both of 

 them are found in a wild state and are very often cultivated. 

 " Naga-imo," " tsukune-imo " and " ichinen-imo " are indeed the 

 names given to the three different cultivated forms of "jinenjo.'" 

 All of these forms produce the large tuberous roots which are 

 used as food. 



