Dkcrmber, 191; 



kxo\vli:dge. 



but only part of this is combined as proteid and a 

 much smaller part as digestible proteid. Only one- 

 seventh part of the nitrogen contained in Shaggy 

 Caps (Coprimis conmtiis. Figure 498) can be digested 

 and made use of bv the human bodv. Of all the toad- 

 stools, the common mushroom (Psalliota dunpestris) 

 is believed to contain the highest percentage of 

 digestible proteid ; yet this is really so small that 

 it is only one forty-seventh of that in beef and 

 one fifty-sixth of that in beans, while it is just 

 about equalled by the proteid contents of cabbage 

 and potatoes. Continuing our comparison with 

 these two vegetables we find that the percentage of 

 fat in mushrooms is about the same as in cabbage, 

 but a little more than in potato, while the carbo- 

 hydrates, though approximately the same in amount 

 as in cabbage, are only a quarter as abundant as in 

 potato. Clearly, then, from the point of view of 

 actual nourishment, we do just as well on cabbage 

 as on any toadstool, and run much less risk. 



But the value of anj- food is not to be measured 

 entirely by the percentage of digestible proteids, 

 carbohydrates and fats that it contains. Man\- 

 substances having no food value are of use as stimu- 

 lants to digestion and aids to assimilation. Their 

 action is in part psychological ; for there is no doubt 

 that pleasant flavours and aromas stimulate the 

 movements of the stomach and the secretion of the 

 digestive juices. 



The conclusion we must come to is, therefore, that 

 certain varieties of toadstool properly cooked arc not 

 undesirable constituents of a meal, but that except 

 in the case of a few kinds, like the common mush- 

 room, they are by no means free from risk. There 

 is no rule to distinguish an edible from a poisonous 

 variety. Dependence on some supposed rule has 

 been responsible for a large proportion of the cases 

 of poisoning. The only way is to get to know each 

 edible species, with all its distinguishing charac- 

 teristics, and to eat no toadstool that does not 

 conform with these in every particular. 



Lastly, of what value are the edible and poisonous 

 properties of toadstools to the toadstool plant ; 

 There can be no doubt but that the truffles w hich are 

 found beneath the soil, and are sought for and rooted 

 up and eagerly devoured by pigs, really like to be 

 thus treated : for by this means the spores are 

 distributed in a manner most suitable for their 

 germination. The trufiles, with their myriads of 

 contained spores, are the fruits of the truftle plant, 

 and their strong scent is as surely designed to make 

 their presence evident to pigs as are the bright 

 colours of many fruits to make them noticeable to 

 birds. The Common Earth Ball {Scleroderma 

 vulgare. Figure 499), a variety of puff ball that has 

 a very thick covering which never spontaneously 

 ruptures, is commonly found perforated in various 

 directions by beetles. No doubt these creatures 

 nibble through the outer covering for what they can 

 get inside, but by so doing they clearly assist in the 

 distribution of the spores. 



Many species of toadstool, including the deadlv 



Death-cup, are found eaten bv slugs, and a friend 

 once told me that she had watched a squirrel for 

 several minutes nibbling a species of Russida with 

 evident relish. Slugs are, however, rather careful of 

 the variety of fungus that they care to tackle. 

 Experiments with slugs kept without food for a 

 couple of days showed that while the Stump Tuft 

 {Aniiillarea inellea), the Emetic Russule {Riisstila 

 cinetica), and the Scarlet Fly Cap {Ainaiiita 

 iniiscaria) were readily eaten, the Sulphur Tuft 

 {HypJiolniiia fascictilare) and the Melon Hygro- 

 pliorus iII\\<ir()plionis priitensis) remained practically 

 untouched. The internal economy of the slug 

 must be very different from our own, for some 

 of those species preferred bv the slug are to us 

 deadly poisonous. It will be seen from the above 

 that several of the bright-coloured species are 

 eaten in nature and one is inclined to wonder 

 whether the bright colours have any value for 

 attractive purposes. That the brilliant tints of so 

 many fungi are due to no mere accident, and are 

 something more than a method for the disposal of 

 material of no further value to the plant, is indicated 

 by their constant presence in certain species, and by 

 their limitation in nearly every case to that part of 

 the toadstool visible from above, and perhaps most 

 of all by the coloured substance in most cases being 

 found only in a very thin layer of tissue on the upper 

 surface of the cap. 



Nevertheless, as will be seen above, a good man\- 

 species, and among them some of the bright 

 coloured, are rarely, if ever, eaten in nature, and 

 moreover, the umbrella-like form which has proved 

 so successful in the struggle for existence that it is 

 found in many thousands of different species of 

 toadstool, is so excellently adapted for the distribu- 

 tion of the light spores by the wind that it is difficult 

 to imagine that it has been evolved for any other 

 purpose. I would suggest, therefore, that the bright 

 colours of toadstools are for the purpose of making 

 them conspicuous so that they may be avoided and 

 neither trodden on nor eaten by mistake by grazing 

 animals. The fact that manj' species of black 

 spored toadstools, Copriiius, Paneoliis, Sfropliaria and 

 Galera are found almost exclusively on the dung of 

 various herbivora, and that the spores of other fungi 

 have been shown to have been present in the 

 alimentary canal of rabbits, must be onl\- taken to 

 indicate that the spores are able to traverse the 

 digestive tract unharmed, and does not show that 

 fungi are ever eaten by these animals. It is much 

 more likely that the numerous and minute spores 

 have settled on some of the regular food of the 

 animal, and have then been swallowed by accident 

 with it. 



But toadstools, especially the gills of those kinds 

 that possess them, are very frequently eaten by 

 slugs, and the observations of \'oglino tend to show- 

 that this is not altogether disadvantageous to the 

 fungus plant : for the germinating spores of species of 

 Riissula and Lacfariiis were found in the digestive 

 tracts of slugs fed on these toadstools. Further, 



