92 NUT GROWING 



Aside from direct obstruction to the entrance of 

 microbes into a tree wound melted paraffin goes still 

 farther into the field of aseptic surgery. It occupies 

 interstices in which sap might collect and ferment, 

 yet at the same time allows new repair cells of the 

 wound to shoot along beneath it safely under cover. 



According to laws of symmetry the parts of a 

 tree are systematically arranged about the long axis 

 of the tree and about the long axis of a branch, twig, 

 or bud. If a spiral line is drawn about a twig it will 

 be observed that a definite series of buds occurs 

 along the spiral line. The number of buds to a com- 

 plete spiral varies with the genus or species. This 

 fact is worthy of note in relation to our newer 

 knowledge relating to axial polarity (the sending of 

 sap contents to definite points in the long or short 

 axis of a branch). It is not unlikely that in bud 

 or scion grafting it may be well to set grafts accord- 

 ing to the spiral which relates to the series of that 

 particular kind of tree if we wish to reproduce nat- 

 ural conditions most nearly. Sap distribution with 

 its nutrient material is sent along definite lines of 

 the tree for definite purpose and polarity in relation 

 to hormones carried by the sap for stimulating 

 growth or for repressing growth is a factor which is 

 perhaps to be reckoned with in relation to points at 

 which grafts may be set to best advantage. 



Nut trees may be grafted according to principles 

 which apply to fruit trees in general but special 

 knowledge is required. Most of the attempts at 

 grafting nut trees were a failure excepting with 



