FILLING OF CAVITIES 107 



MATERIALS 



Dressings. — It is natural, when the materials 

 employed in the treatment of cavities are men- 

 tioned, to think first of concrete and the like. But 

 of first importance are the dressings used on the in- 

 terior of the cavity before the filling is put in. 

 Logically, those materials are practically the same 

 as the materials used for wound dressings, a sub- 

 ject considered at length in a previous chapter. 



The materials of greatest value as dressings for 

 cavities are creosote, the best preliminary disin- 

 fectant and preservative ; coal tar, mainly of value 

 when the cavity is dry and well-drained, and the 

 various forms of fluxed asphalt. 



Fillings. — A large number of different materials 

 have been or are being used for filling trees. Con- 

 crete is of course the commonest of them. Lately, 

 asphalt has been supplanting concrete for many 

 kinds of work. In the present division of the 

 chapter the principal materials and the ways in 

 which they are prepared for use will be discussed, 

 leaving for a later division an account of how they 

 are put into the tree. 



Concrete. — Cement is a fairly easy material to 

 handle. Any one can mix up a pail of cement with 

 a wheelbarrow or two of gravel, pour it into a soap 

 box, and make a passable horse-block. But the 

 ease with which a certain kind of success is attained 



