59 



the stem would continue to deposit new 

 growth on it from above. This tree is still 

 alive— 1844. 



I imagine that the reason that this tree 

 has continued to live is, that each year it 

 has shot out new branches from below the 

 scar. These branches have each year been 

 eaten off by cattle ; but they have elabo- 

 rated and returned sufficient sap to nourish 

 and to keep the root alive. I imagine that 

 if these branches had been allowed to 

 grow they would have taken so much sap 

 that it would have ceased to be forced up 

 the old stem, and that the old stem would 

 have died. But the existence of this tree 

 and of rung branches proves to ocular 

 demonstration that the sap goes up the 

 heart wood, since on the scar and on the 

 rings no new wood or alburnum is depo- 

 sited. It is true that the number of rings 

 of what is called sap wood or alburnum 

 differ in different trees, and even parts of 

 the rings of a tree may ripen sooner into 



