69 
Hxpprimeiital 
The experiments were designed to test the effect of heating, drying 
ond boiling on the stinging properties of the Gympie (Laportea moroides) as 
this species possesses by far the most virulent stinging hairs of the 
Australian species. 
In the first experiment, which was carried out at Kin Kin, a fresh 
green leaf was placed In o heated oven. The thermometer registered over 
110° C. Unfortunately this thermometer was only graduated to 
110° C. but it was the most suitable available. After 10 minutes the 
leaf blade was curled up and dark brown. The leaf stalk only was greenish 
brown and owing to the effect of the heat it was longitudinally corrugated 
ond hod contracted from 6 mm. to 4 mm. in diometer. At this stage the 
leaf was removed from the oven as further heating would have made it 
useless for experimental purposes on account of its brittleness. When 
rubbed on the skin of the forearm the leaf blade broke into fragments, 
but the 5.5 cm. stalk remained intact and was rubbed on together with 
the fragments of the blade. 
Within a few seconds the intense stinging sensation was felt. The 
skin immediately became red and broke out into small white lumps 
(? sebaceous swellings) 1-2 mm. in diameter and larger white lumps 
4-6 mm. in diameter. Later the same day slight pain was felt at the 
elbow and in the upper arm but no underarm poin was experienced. The 
stinging sensation remained continuous and intense throughout the day. 
Twenty-four hours after the beginning of the experiment the stinging 
sensation was still felt and occasional twinges of pain were experienced. 
The stinging sensation was still experienced after washing and drying three 
months after the experiment was carried out. 
Three days after the beginning of the experiment the white areas 
-disappeared and the redness disappeared on the fifth day. 
Immediately after rubbing the leaf on the forearm some stinging 
hairs were removed from the leaf stalk and examined microscopically. The 
heating had caused shrinking and plasmolysis of the protoplasm and 
bleaching of the colours of the cell contents. 
In the second experiment a herbarium specimen of the Gympie was 
used at the suggestion of my friend Mr. S. L. Everist. The leaf used is 
from a specimen collected at Paimwoods in May, 1909. It is propitious 
to the present occasion that the specimen chosen was collected by C. T. 
White whose memory we venerate with respect and affection tonight. The 
leaf was warmed for a few seconds to restore its rigidity. The upper 
surface was then rubbed on the left side of the shin. After a latent period 
of several minutes the stinging sensation commenced and gained in 
intensity for about half an hour. The stinging sensation was continuous 
throughout the day and at night. No reddening of the skin was observed. 
On the second day the stinging sensation was felt slightly after washing 
and drying. On the third day it was felt several times during the day and 
was not felt on the fourth day. 
Before rubbing the leaf on the skin a slide showing the hairs was 
made. Microscopic examination showed that most of the hairs had lost 
their straight and rigid appearance and were shrunken, curved and bent. 
This observation indicates thot the hairs had lost much of their effective- 
ness os organs of penetration in contrast with the hairs of green specimens. 
This circumstance emphasises the stable character of the stinging principle 
particularly when it is remembered that the leaf used in the experiment 
was kept between sheets of absorbent paper for 46 years. 
In the third experiment a leaf of Laportea moroides which had been 
dried between absorbent paper for 3 weeks was boiled for 20 minutes and 
allowed to dry in air. The upper surface of the leaf was then rubbed on 
the right side of the shin. The stinging sensation was first felt 15 seconds 
after rubbing. Slight redness of the skin was evident 10 minutes after 
rubbing, but was more conspicuous li hours ofter rubbing. The greatest 
