183 



venenata and E. vadicans are also poisonous to some persons, 

 but not to all alike. The latter of these species, Rhus 

 radieans, is the plant which caused the poisonous effects 

 described in these notes. 



The plant is common in North America, where it is known 

 as poison ivy. The air impregnated with its volatile exhala- 

 tions is capable of poisoning many persons, more especially 

 in hot weather, causing a kind of violent erysipelas, accom- 

 panied by erysipelatous eruptions. Some persons are wholly 

 unaffected by it, and a case is given where one member of a 

 « family could handle the plant with impunity, while another 



would be affected by mere proximity alone without contact. 

 Persons of irritable temperaments are said to be more sus- 

 ceptible than others. 



The particular plant in question has been in the garden 

 for many years. I am unable to say how it was obtained, or 

 whether more were received at the same time or not. For 

 some thirty years it has occupied the same position in the 

 gardens, and for a long time was without specific name, being 

 known as Rhus species. Later, on examination, I believed 

 it to be Bhus radieans, the only doubt in the matter being 

 that it had not, so far as I was aware, exercised any poisonous 

 effects at any time. 



The natural habit of the plant is to spread and root on the 

 ground like ivy, but it is capable of climbing up any support 

 that it may happen to be near, even to the top of high trees. 

 Being of rapid growth, it soon forms a large clump on the 

 ground ; the plant now under consideration was about 6ft. in 

 height, and covered upwards of a rod of ground. To restrict 

 it to these dimensions it became necessary from time to time 

 to considerably reduce it, these reductions at times amounting 

 to about one-third of the whole ; the plant, therefore, has 

 hitherto been freely handled without, so far as is known, 

 having produced any ill-effects. I say so far as is known, 

 because it is possible that it may have done so without the 

 cause being suspected. The symptoms do not develop for 

 some time after the influence has been exercised, rarely under 

 48 hours, being very similar to those of ordinary erysipelas 

 they would be ascribed to an attack of that malady, and the 

 cause producing them would not be suspected. 



It is very probable that the plant may have a more poison- 

 ous influence at one season than another, and to this I am 

 inclined to ascribe its effects in the present case, when 

 six persons became poisoned by it at one time, two at least 

 to a serious extent. 



In the ordinary course of routine garden operations, any 

 reduction or thinning necessary would have taken place 

 earlier in the season, when the plant, which is deciduous, was 



