1897] F- T. Shutt. — The Poison of Poison Ivy. 107 



plant chemistry advanced step by step, it was attributed more 

 concretely to a specific gas, a volatile alkaloid, and a volatile 

 acid like formic acid. More recently still, bacteria have been 

 accused of causing the affection. Experiments have seemed to 

 verify these ideas in turn, but the falsity of all has at last been 

 proved by the discovery of a more tangible compound. In 

 January, 1895, Dr. Franz Pfaff, of Harvard University, an- 

 nounced that the poison is in reality a non-volatile oil. Num- 

 erous experiments have been performed with the purified oil> 

 and it has been shown to produce exactly the same effect as the 

 plant itself Dr. Pfaff has called this substance ' toxicodendrol.' 

 It is found in all parts of the plant, even in the wood after long 

 drying. Like all oils, it is insoluble in water, and therefore can- 

 not be washed from the skin with water alone. Alcohol dis- 

 solves it readily. Alkalies saponify it, and thus render it inert, 

 but this result is more easily obtained by an alcoholic solution 

 of the sugar of lead (lead acetate)." 



The two chief points of interest to our readers arc : the 

 establishment ot the fact that the poison is non-volatile and. 

 therefore, that actual contact of the leaves with the skin is 

 necessary to cause the poisoning ; and, secondly, that a remedy 

 has been iound that is at once simple and efficacious. The 

 writer, as the result of many trials, in which he experimented 

 on himself and others, says that " applications of an alcoholic 

 solution of the sugar of lead always give immediate and per- 

 manent relief" This is certainly to be regarded as a valuable 

 discovery. Respecting the application of the remedy, the writer 

 concludes as follows : — 



" In practice it is not desirable to use strong alcohol, which 

 is apt to be too irritating to a sensitive surface, but a weaker 

 grade of from 50 to 75 per cent, should be preferred, and to this 

 the powdered sugar of lead is to be added until no more will 

 dissolve. The milky fluid should then be well rubbed into the 



