NOTES ON THE VARIOUS SPECIES 243 



be impossible, and the holes are yet filled, simply 

 for the sake of appearances, many of those pre- 

 cautions and measures which are indispensable to 

 an ideal operation need not be taken. The proc- 

 esses to be omitted and the short-cuts which can 

 be used will suggest themselves to one who under- 

 stands the principles upon which the work of fill- 

 ing is based. 



When the second purpose dominates we may 

 presume that the factor of expense is practically 

 negligible. It is safest, however, for the work- 

 man to warn the owner, before he begins, of the 

 probable expensiveness and doubtful value of the 

 work, if the decay is so advanced as to make suc- 

 cess problematical. Then let him go ahead and 

 do the very best job that skill and good materials 

 will turn out. And he must not fail to see to it 

 that the repair work is supplemented and given 

 the best chance of being successful by careful prun- 

 ing, spraying, and such soil treatment as may be 

 necessary. 



With the consideration of the value of cavity 

 work in apple trees whose sole value is economic, 

 we come to a very different subject. Here the 

 factors are more tangible. Costs must be figured 

 carefully in relation to returns. Expenditures 

 must be fairly sure to accomplish the purpose for 

 which they are made. 



After considerable experience and observation, 



