GRUUrS OF PLANTS. 33 



times it is shiny and white. While it does not possess the warty 

 scales found in the fly agaric, it has occasionally a few mem- 

 branous patches. 



The Toxic Principles in Poisonous Fungi. Ihe deadlv 

 agaric (A)iianita phalloides) is the cause of the greatest number 

 of cases of mushroom poisoning. According to Al)cl and Ford 

 it contains two toxic principles: (i) Amanita-hemolysin a IjIcmjcI- 

 laking principle, which is a very sensitive glucoside, that is. pre- 

 cipitated by alcohol and destroyed ])y heating to 70 C. and 1)\- 

 the action of digestive ferments; (2) AmaniUHoxin which is 

 soluble in alcohol and not destroyed by the action of heat or 

 ferments. The latter principle is the important poisonous prin- 

 ciple in mushroom poisoning and is probably the most toxic 

 principle known, 0.4 of a milligramme killing a guinea ])ig 

 within 24 liours. " The majority of individuals poisoned by the 

 '* deadly amanita " die, but recovery is not impossil)lc when 

 small amounts of the fungus are eaten, especially if the stomach 

 be very promptly emptied, either naturally or artificially." 



The fly agaric (Amanita muscaria) owes its toxicity to mus- 

 carine, an alcohol-soluble crystalline substance. It is supposed 

 bv Ford that the fly agaric may contain another poisonous constit- 

 uent. In cases of poisoning atropine has been successfully ad- 

 ministered hypodermically in doses of y^^ to -V of a grain. 



It is stated that the A. muscaria used by the peasants of the 

 Caucasus in the preparation of an intoxicating beverage is 

 deficient in muscarine. 



The question as to whether the ordinary edible mushrooms, 

 as distinguished from the ]:)oisonous toadstools, may not in cer- 

 tain localities or at certain periods of the year be the cause of 

 fatal intoxication is answered by Ford in the negative. He 

 states (Science, 30, p. 105. July 2^, 1909) that there are no 

 authentic cases of poisoning from the black or brown spored 

 agarics, although old and badly decomposed specimens may cause 

 transient illness. 



Economic Uses of Fungi. A large number of the Fungi, 

 particularly of the Basidiomycetes, are used for food. There 

 are. however, only a few of these which enter the market. These 

 are derived chiefly from A_i^aricus campesfris (Fig. 21, illus.^ i) 

 and Agaric us arvcnis, although some other species of Agancus 



