230 RESEARCHES ON FUNGI 



The results just given indicate that, whilst species of Armillaria, 

 Russula, Amanita, and Omphalia are relished by the slugs tested, 

 species of Lactarius, Hygrophorus, Laccaria, Hypholoma, and 

 Cantharellus are disliked to a greater or less extent. 



Lactarius rufus to our taste is exceedingly acrid, and its 

 peculiar latex may well be the cause of its being but very slightly 

 eaten by hungry slugs. In nature, among thousands of fruit- 

 bodies of this species, I have very rarely found one slug-eaten, 

 and then very slightly. Once a specimen was noticed which, 

 from the slime left all over the gills, had evidently been visited 

 by a slug, but which had not been attacked ; whereas fruit- 

 bodies of Russula citrina close by had been seriously damaged. 

 This seems to afford distinct evidence that the one species is 

 chemically protected from slugs and that the other is not. 

 Lactarius glyciosmus contains a peculiar aromatic substance, and 

 it may be this which causes the fruit-bodies to be left uneaten 

 by Agriolimax agrestis. 



The fruit-bodies of most species of Hygrophorus are glutinous 

 or viscid and their gills are waxy. Possibly it is their physical 

 nature which renders them distasteful to slugs. The exact causes 

 which render these and other fruit-bodies, such as those of 

 Hypholoma fasciculare and Laccaria laccata, inedible, require 

 further investigation. 



Mere acridity of itself is not sufficient to cause a fungus to be 

 rejected by slugs. Every one is agreed that the fruit-bodies of 

 Russula emetica are very acrid; yet all three species of slugs 

 tested eat them with avidity. 



Slugs can feed upon a number of fruit-bodies which are 

 poisonous to man. Thus Amanita muscaria was eaten vora- 

 ciously by all three of the slugs tested and without any ill effects 

 to them. Amanita phalloides is one of the most poisonous 

 of fungi, and yet in nature one may often find slug-eaten fruit- 

 bodies of this species. It is evident that muscarine, phalline, and 

 other toxines present in species of Amanita have no protective 

 significance so far as slugs are concerned. 



