GRAFTING 91 



affairs and fruitfulness of the tree as it does with 

 animals. 



When a tree has received a cut, materials for pur- 

 poses of repair are sent to that point in the tree. 

 The tree, conscious and alive to a recognition of its 

 needs, elaborates special material for repair purposes, 

 somewhat different from that belonging to material 

 for growth purposes. The tree sends protective ma- 

 terial to wounds along with repair material (protec- 

 tion against interference from microbes). Microbes 

 immediately begin to attack wood, sap, and stored 

 food at the site of a cut. They attack also the ma- 

 terials newly thrown out for purposes of repair 

 because all of these things belong to their own break- 

 fast and dinner. Microbes are both bacterial and 

 fungous. In grafting work we are obliged to con- 

 sider this point in order to lessen as far as possible 

 the dangers from microbic attack, constituting the 

 grafter's chief trouble. Antiseptics are not com- 

 monly used in plant grafting work as they are in 

 animal surgery 1 but a weak solution of copper salts 

 would undoubtedly halt the development of many 

 fungous microbes. We shall carry antiseptic or 

 aseptic surgery farther than it has been carried pre- 

 viously in our plant surgery of to-morrow. If the 

 wound in the tree has been covered with white lead 

 paint or with melted paraffin, mechanical obstruction 

 is offered to the entrance of microbes into sap and 

 other organic materials which would serve as a land 

 of milk and honey for them. 



