92 SCIENCE FROM AN EASY CHAIR 



degree, accompanied by the formation of blisters and 

 breaking of the skin. The affection spread to the body, 

 and caused constant pain and corresponding prostration. 

 Her medical attendants were unable either to cure or to 

 account for her condition. After some months she left 

 home, and entirely recovered. But every year the same 

 distressing and disfiguring illness attacked her (com- 

 mencing in the month of June), and disappeared as soon 

 as she left her house, only to return when she came back 

 to it. The doctors spoke of her affliction as a mysterious 

 form of erysipelas, and even suggested blood-poisoning 

 as the cause. For long periods she was so ill and in so 

 much pain that she was unable to see her friends, and 

 her life was at times in danger. 



Two years ago a weekly newspaper published an 

 account, written by a correspondent, of an illness from 

 which he had suffered exactly agreeing with that which 

 had for so many years tortured my friend's wife. This 

 writer stated that he had ascertained that the disease 

 was due to the action of a poison given off by a creeper 

 which grew on the walls of his house. He had supposed 

 this plant to be a Virginian creeper ; but he had dis- 

 covered that it was in reality the Californian poison- vine 

 called by botanists Rhus toxicodendron. The terribly 

 poisonous nature of this plant is well-known to the 

 people of the United States. It is one of the sumach 

 trees, of which other poisonous kinds are known, whilst 

 more than one species is used (especially in Japan) for 

 preparing a resinous varnish which is used in the manu- 

 facture of " lacquered " articles. The writer in the weekly 

 paper stated that he had cut down and burnt the poison- 

 vine which grew on the walls of his house, and that his 

 sufferings had ceased. My friend happened to read this 

 account, and immediately examined his own house. He 

 found a creeper resembling a Virginian creeper, but 



