67 



haps, to infiucnce heredity tendencies so as to get stocks to accept 

 scions uuire readily, it is not the major issue for most of us just now. 

 Next sprin^^ we will take what heredity has given us and be satis- 

 fied. However, it aj)])ears certain that our results in grafting the 

 various stocks we now have will depend largelv on our ability to: 



1. Regulate jjlant circulation. 



2. Stimulate cellular activity to a point compatiMe with wound 

 repair, defensive and growing ):)roeesses. 



8. Control jjlant cell nutrition. 



One of the very first things we physicians do upon seeing a patient 

 is to investigate his circulation. If the pressure is too low or too high, 

 for ,iny reason, we immediately take measures to correct it, because we 

 kiu>w that disastrous results will quickly follow if that is not looked 

 after. Plant circulation, or sap flow, is no less important. Mr. Riehl, 

 Mr. . I ones and Dr. Morris made great strides when they advanced the 

 ideas of covering the wound and the scion completely to prevent evapor- 

 ation, thereby also controlling the sap pressure. With the exception 

 of shading, pruning and defoliating, this is about the only method we 

 have of preventing evaporation. Defoliation, of course, interferes with 

 tlie tree's ))ower of growth. Controlling the humidity is probably 

 not practical on a large scale. 



A proper and careful cutting of the tree beforehand is important. 

 It appears that to cut the to]) completely out while the tree is dormant, 

 so diisru])ts the routine circulation that the few lower branches which 

 are left intact, are well taken care of and, it seems to me, that this, 

 together witii tlie stimulation of WOUND REPAIR by cutting and al- 

 h>wing time enough for the cells to get into action, was the jirinie rea- 

 .son for the 100% success in the three Hales and the cause of the 

 100% failure in the other Hales tree. 



Other methods of controlling the circulation are of course drainage, 

 Irrigation, niidehiiig, location of tlie orchard, j)lacing of condensers of 

 iiioislurc. such as stones and other hard substances beneath the trees, 

 and many other contrivances which arc in use and which I shall not 

 discuss. 



With reference to stinndation of cellular activity we are consid- 

 erably concerned. In medicine I have found the subject of wound 

 repair and immunity most interesting, the two subjects seeming to be 

 more or less related. Some animals will repair wounds and immunize 

 readily, while others will not. In a general way young healthy animals 



