64 A TEXT-BOOK OF BOTANY. 



and sometimes reddish ; the surface is smooth, with prominent, 

 angular, warty scales, which can be easily scraped off. 



The deadly agaric (Fig. 34, illus. 2) somewhat resembles the 

 fly agaric and also dift'ers from the common mushroom in not 

 usually growing in pastures. It occurs singly, but not in groups, 

 in woods and borders of fields. The gills and stipe are white, 

 the latter, when young, having a number of mycelial threads 

 running through it. The base is quite bulbous, the upper part of 

 the bulb having a sac-like membrane called the volva. The pileus 

 may vary from any shade of dull yellow to olive, although some- 

 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. — The deadly 

 agaric {Amanita phalloides) is the cause of the greatest number 

 of cases of mushroom poisoning. According to Abel and Ford, 

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

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

 cipitated by alcohol, destroyed by heating to 70° C. and by 

 the action of digestive ferments; (2) Amanita-toxin, which is 

 soluble in alcohol, is 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 pig within 

 24 hours. " The majority of individuals poisoned by the ' deadly 

 amanita ' die, but recovery is not impossible 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 

 by 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^o to 5^0 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 poisonous toadstools, may not in cer- 



