582 EEPOET OF STATE GEOLOGIST. 



to verify these claims, although, some cases of severe poisoning are un- 

 doubtedly attributable to this plant. 



In all of the plants cited above, the poisonous property is some sub- 

 stance within the plant body. Of the entire number, only two, the 

 poison ivy and poison elder, are to be regarded as generally poisonous. 

 The others act as poisons only exceptionally, affecting persons with 

 delicate, sensitive skins, or those who, for some reason not understood, 

 are peculiarly susceptible to plant poisons. 



As anything may be regarded as a poison which produces an irrita- 

 tion or inflammation of the skin, it is proper to include some plants 

 which, through mechanical contrivances, produce much the same 

 effects as do those possessing a poisonous principle. 



The cockle bur (Xanthium strumarium) acts as a skin irritant on 

 account of the dust and hairs with which it is covered. 



The Burdock (Arctium Lappa) is irritating apparently almost en- 

 tirely because of its defensive armor. The leaves irritate because of 

 their roughness and the burs on account of the sharp, fragile spinous 

 processes. These latter work their way into the skin, producing great 

 irritation and often festering sores. 



In this class, also, are to be put the thistles (Carduus), although 

 the irritation produced by them is usually much more transient than 

 that caused by the burdock. 



The common Nettle (Urtica gracilis) and the Wood-nettle (Urti- 

 castrum divarication) possess stinging hairs and also an acid principle, 

 the two combining to produce the intolerable burning which follows 

 the lightest handling of either of these plants. The best treatment is 

 a persistent bathing of the affected parts in cold water, this soon 

 relieving the burning and reducing the inflammation. 



The common Mullein (Verbascum Thapsus) produces irritation by 

 the action of its woolly hairs. So vigorous is this action that its leaves 

 are often applied externally to the throat as a counter-irritant. 



Plants of this type, however, are readily recognized as skin irritants, 

 and are therefore much less likely to work harm than those of the first 

 class. N 



PLANTS POISONOUS WHEN TAKEN INTO THE SYSTEM. 



In this class of poisonous plants the first rank is easily taken by the 

 Spotted Cowbane or Water Hemlock (Cicuta maculata). It is found 

 throughout the State in swamps or low grounds, and is so virulent in 

 its effect that it should be recognized at sight. It is only by this 

 general recognition of the plant and a knowledge of its poisonous 



