4 8 
NOTE ON A BOUGH OF PARA-RUBBER 
DESTROYED BY ROT. 
In a Para rubber tree in the Botanic Gardens which had several 
erect branches at the top, it was noticed that a good deal of rubber 
had been dropping and was still exuding. A man was sent up the 
tree and cut off the bough, which was then sawn in two to observe 
the cause of this. The bough is 5 | inches in diameter on one side 
(the outer one) a smaller branch had fallen or been broken off and 
the wound i inch across had not healed, but the wood had decayed 
forming a space, 7 inches long and 3 inches wide. Fungi had 
attacked the wood and the decomposition had spread downwards 
for about 9 inches and upwards for 20 inches. I he bark on this 
side was nearly twice as thick as that on the other side (the inner 
side) and was quite dry and perforated by beetles, which had how- 
ever not penetrated into the living wood. The very small beetles, 
belonged to the group of shot-borers which habitually feed on 
dead wood, and from their holes the rubber had exuded. Here 
and there in the dead bark were spaces which were filled with rub- 
ber but no liquid latex could be seen in this part of the bark. The 
living bark exuded .latex freely, but in greatest abundance just 
above the point to which the death of the wood had reached, and 
much more freely than from the thinner bark on the inner side of 
the tree. It appears then that in the case of an injury of this kind 
the wood dies before the bark covering it. As the death caused 
by the fungus spreads vertically up or down the stem the beetles 
attack the decaying wood but do not touch the living tissue. At the 
same time the flow of latex to the affected part increases so that 
the greatest amount is to be found near the injury. This increase 
of flow in the neighbourhood of an injury, corresponds to what 
has been named ‘‘calling the latex. ” It is known that the first 
wound inflicted on a tree produces but little milk, but when the 
wound is re-opened daily, the flow gradually increases. In the 
Amazons method of tapping described in another article, a cut is 
made the first day high up, and next day a fresh one, two or three 
inches lower, and so on to the foot of the tree, the first wound 
produces very little latex, the second more and so on. I his is not 
due to the fact that there is more latex low down the tree than 
above, but rather due to the wound action, which appears to pro- 
duce a flow of latex to the wounded side of the trunk. A tree thus 
is said to milk better when it is accustomed to it. 
JOURNEY TO A RUBBER PLANTATION ON THE 
ISTHMUS OF COLUMBIA. 
By Dr. C. O. Weber. 
The well known difficulty of investigating satisfactorily in Europe 
any of the numerous questions of importance connected with the 
collection of the latex from the rubber trees, its composition, and 
the most satisfactory manner of converting it into india rubber, 
