34 



Bertrand named the gummy substance that was separated 

 from Japanese lac, "Laccase". He has since used a somewhat 

 different method of separation in order to prepare it from other 

 plants, like potatoes, turnips, beets, artichokes, asparagus, apples, 

 pears, etc. The fresh parts of the plants are crushed, the juice 

 expressed and after saturating with chloroform allowed to stand 

 24 hours when a coagulum forms and the juice is separated and 

 the gum is then precipitated by alcohol. 



Bourquelot and Bertrand 36 examined about 200 species of 

 mushrooms of which they give the following: 



GENERA EXAMINED ACTIVE INACTIVE 



Russule 18 18 o 



Lactarius 20 18 2 



Psalliota 5 4 i 



Boletus 18 10 8 



Clitocybe 9 5 4 



Marasmius 6 o 6 



Cortinarius 12 i n 



Inocybe 6 i 5 



Amanite 7 2 5 



Hygrophorius 6 o 6 



The parts of plants which contain the least chlorophyl con- 

 tain the most laccase. 



Bertrand 37 has shown by experimenting upon such substances 

 as hydroquinone, pyrogallol, gallic acid, etc., that the soluble 

 ferments like laccase act by direct oxidation and that under its 

 influence these bodies, in the presence of air, take up oxygen and 

 give off carbon dioxide. He found that the phenols most easily 

 acted upon are those having hydroxyl in the ortho or para posi- 

 tion. When in the meta position they are oxidized with great 

 difficulty. 



On adding laccase to a solution of hydroquinone it changes 

 to a deep red color and after some time green crystals are formed 

 and the solution has the characteristic odor of quinone. 



Bertrand 88 states that the darkening of certain substances 

 as the dahlia, beet, etc., is due to the oxidation of ty rosin under 

 the influence of soluble ferments. But that tyrosin resists in- 

 definitely the action of gaseous oxygen in the presence of laccase, 

 even in strong solutions ;therefore the blackening of the tyrosin 



30 Compt. rend. 121, p. 166 & 783, 1895. 



37 Compt. rend. 120, p. 226, 1895. 



38 Compt. rend. 122, p. 1215, 1896. 



