Séance du i3 Juin 1917 515 
continues to work among thaï plant. In tliirty hours from com- 
mencing to work therein his symptoms are severe enough lo 
seriously attract his attention and he thinks, perhaps correctly, 
that he is attacked by the same éruption as that from vvhich he 
had once suffered, as mentioned above, on another part of the 
Nile. 
The symptoms continue and get worse during the remaining 
six days of his stay at Canetti, but within a few hours of leaving 
t h is place he begins to feel better and in 6 days later he is prac- 
tically well, except for very slight trouble vvith his legs which 
is increased temporarily by his long walk, but even this subsides 
in another 6 days when he completely recovers without any 
medical treatment. 
Thereare onlylwo possible causes for an éruption of the nature 
described above, taking place in a perfectly healthy man, and 
these are firstly some exhalations from a plant or secondly the 
irritation of some mite derived from the same plant or neigh- 
bourhood. 
The patient in the présent case being a well trained zoologist 
would hardly be likely to miss observing mites on the plants 
among which he was working and he failed to observe any, nor 
were we able to find any 011 specimens forwarded to us and 
therefore by process of exclusion we are compelled to consider 
the plant ilself, for which he probably lias an idiosyncrasy as 
he strongly objected to the odour arising therefrom and because 
he noticed that his headache always began after working for a 
short space therein, although at the time he had never heard 
that plants could cause such an éruption. 
Ætiology. — In order to settle the causation of the éruption, 
we obtained, by the kindness of Colonel Jackson, (T B., Gover- 
nor of Dongola, a quantity of the rue which, because of its long 
journey, had become somewhat dry. 
The patient was brought into contact with the plant about 
6.3o P. M. one evening and that night he suffered from heada¬ 
che and next day, i. e. in about 18 hours after rubbingsome of 
the leavesand llowers on his forearm for a few seconds, an érup¬ 
tion appeared on this région exactly similar in appearance and 
with similar symptoms only less severe than that from which he 
originally suffered. 
