96 SCIENCE FROM AN EASY CHAIR 



of the oil in the skin or clothes to have slight attacks. 

 According to a writer who two years ago gave in the 

 Spectator an account of his own case, the first symptom 

 of an attack is almost invariably a redness and irritation 

 of the eyelids, accompanied by shivering. In a few hours 

 the eyelids are closed, the features unrecognisable, and 

 the skin covered with little blisters. Then the lips swell 

 enormously, the glands of the neck also. In four days 

 the arms and hands are reached, each finger appearing as 

 if terribly scalded and requiring separate bandaging. Then 

 sometimes the lower limbs are involved. After ten days 

 the attack passes off, leaving the patient in a pitiable 

 state of weakness to grow a new skin and recover from 

 other painful results of the poisoning. But no immunity 

 is conferred by an attack ; the unhappy victim (who is 

 ignorant of the cause of his sufferings) may, and fre- 

 quently does, get a new dose of the poison as soon as he 

 has recovered, and the whole course of the illness has again 

 to be passed through. If this account should fall into 

 the hands of any one who is being unwittingly poisoned 

 by the American poison-vine, and may therefore be saved 

 by what I have written from further suffering, I shall be 

 greatly pleased. 



There are very few plants which have a power of diffus- 

 ing poison around them ; usually it is necessary to touch 

 or to eat portions of a plant before it can exert any 

 poisonous effect. The eighteenth-century story of the 

 upas-tree of Java, which was fabled to fill a whole valley 

 with its poisonous emanation, and to cause the death of 

 animals and birds at a distance of fifteen miles, is now 

 known to be a romantic invention. The tree in question 

 is merely one having a poisonous juice which was ex- 

 tracted and used by the wilder races of Java as an arrow 

 poison. It is stated that one of the stinging-nettles of 

 tropical India has such virulent poison and such an 



