AND IN EPIDEMICS. 59 



become poisonous, and some of the poisonous kinds become 

 esculent. The Ag. Piperatus, according to Haller, is poi- 

 sonous in France, but esculent in Russia. The Amanita 

 Muscaria, an intoxicating food in Siberia, becomes a deadly 

 poison in the south of Europe. Fodere states, that the 

 most delightful of the esculent mushrooms of France be- 

 come unsafe after prolonged rains. The same thing occurs 

 in South Carolina, where, in very wet weather, it be- 

 comes necessary to remove the mushrooms, or keep up 

 the hogs, that they may not be poisoned by that which, 

 in common weather, is eaten to advantage. 



As the power of growth, and the quality of the fungi, 

 are so dependent on slight causes, we can scarcely wonder 

 that a plant of this class may be noxious as produced at 

 night, and hurtless as developed by day. Even if pro- 

 duced alike in both, the poison of the cryptogami is so 

 subtle and fugacious, that a little daylight or sunshine 

 may totally alter its properties. Foderd (Med. Legal) 

 tells us that most fungi become safe when they have been 

 dried, which Christison thinks probable, as their poisonous 

 properties appear to depend on a volatile principle. Fi- 

 nally, Letellier assures us, that the acrid principle of the 

 agarics is so very fugacious, that it disappears on boiling, 

 or drying, or by maceration in weak acids, alkalies, or 

 alcohol. If, after all this, we find a malarious poison active 

 at night, and not by day, it does not present an objection to 

 the theory proposed, but affords some support to it, since 

 we know of no other things which are so materially af- 

 fected by light and heat. 



I am now, gentlemen, about to show you a very curi- 

 ous part of this singular subject, the extraordinary asso- 

 ciation of fungous life with the existence and propagation 

 of great epidemics and intense endemics. Not only are 



