70 RESEARCHES ON FUNGI 



its spores, was crushed up in a mortar, and the contents of the 

 mortar were then filtered through three thicknesses of filter-paper. 

 The filtrate, which was spore-free and brownish, was allowed to 

 stand for 24 hours during which time it darkened in colour. It 

 was then used to write the words shown in Fig. 44. A comparison 

 shows that the writing in Fig. 43 is much darker than that in Fig. 44, 

 thus proving that the intense blackness of the Coprinus ink of 

 C. sterquilinus is due chiefly to the presence of the spores. Experi- 



Wrirren wirh rhe 



Sbopeless Juice of 



Cobrinus s^&rQUllinus. 



Fig. 44. — The words were written with a brush dipped in the juice of an 

 autodigested pileus of Coprinus sterquilinus, from which the spores had 

 been removed by filtration. The dark colour of the ink is here due 

 solely to a dark brown pigment produced by the action of one or more 

 oxidising enzymes. Reduced to two-thirds the original size. 



ment showed that the darkening of the fluid in which the spores are 

 suspended is an oxidative process and is brought about by an 

 oxidase present in the tissues of the fruit-body before autodigestion 

 takes place. 



Coprinus ink was made and used by Bulhard more than one 

 hundred years ago. In his great work, BulHard ^ illustrated V Agaric 

 atramentaire {Coprinus atramentarius) and VAgaric typhoide {C. 

 comatus), and in the description of the latter referred to the brownish 

 ink (encre bistree) as excellent for washes and for pen-and-ink 



1 P. Bulliard, Herbier de la France, Paris, 1784, p. 406. 



