6i8 



The bast ring (&) has been less affected ; only the contents of the young 

 bast cells are usually found to be brown, corresponding to the filling of the 



Pig-. 148. A healed internal frost wound on a young oak branch, caused by injury 



from a May frost. 



,- canibial zone, z zigzagr line with swollen cell walls, g vessels in the normal wood. 



Explanation of the other letters to be found in the text. 



different ducts of the wood ring with a reddish yellow, gum-like substance. 

 The bark parenchyma contains single, brown groups. No special phenomena 



