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healing of the wound is performed by the activity of the cambium. 

 As the growth of the cambium proceeds a soft cushion or " callus " 

 is formed, looking like a thickened lip to each margin of the cut. 

 The "callus " growth proceed over the surface of the exposed wood 

 and, eventually, by the meeting and fusion of the lips the wound is 

 healed. The exposed surface of wood becomes covered with a layer 

 •of what is known as "wound wood," in which the vessels are short 

 and irregularly arranged. This " wound wood " is produced in 

 excess of the amount developed by the surrounding parts of the 

 cambium with the result that the surface of the back overlying the 

 wood which was originally exposed is raised into a bump. 



The surface irregularities of thi; kind are, therefore, easily 

 -avoided by obtaining from wounding the wood in tapping. 



The ultimate fate of such structures is that they eventually 

 become obliterated by the further production of normal wood by the 

 cambium at those points. 



A good example of the origin of these structures is given by 

 Fetch, in which a tree hadNbeen tapped on the system of separate 

 Vs which had penetrated to the wood ; on removing the bark the 

 wood was found to be raised in Vs, each of which corresponded with 

 a tapping cut. 



THE CHIEF DISEASES OF PARA RUBBER IN 

 MALAYA AND CEYLON. 



The works of M. George Vernet, on Rubber, are always worth 

 reading, and his recent publication Sur les principales Maladies de 

 THevea dans 'la peninsule Malaise a Java et a Ceylon, is no excep- 

 tion. He describes and illustrates with photographs the chief pests 

 which attack our Heveas. They are the following : — 



I. White root fungus (Champignon blanc des racines.) This 

 is known by its fine white filaments which form characteristic 

 strands. This is the mycelium which we, have always believed to be 

 that of Fomes seniitostus. M. Vernet discusses the question at some 

 length. Doubt seems to have been thrown on the identification 

 chiefly on account of the fructification of Fomes not having always 

 been seen on roots or trees attacked by the white fungus. I have not 

 the slightest doubt myself on the subject. Every tree and every root of 

 sufficient size bearing the white fungus will here, especially in wet 

 weather, produce the characteristic brackets of Fomes. Where the 

 ground is thoroughly infected with the white fungu<, Fomes is ver}^ 

 abundant and no other fungus usually visible. 



" Let us not forget," says M. Vernet " that one only meets with 

 Fomes semitostus on dead wood not on living organs." It is true that 

 by the time the fructification is developed the part of the tree that 

 bears it is dead, but it does occur on trees not yet dead and only 

 affected as far as the fungus has gone. There are many of the bracket 



