100 NUT GROWING 



grafting may be done from March to August in the 

 latitude of New York, but bud grafting may be done 

 well into September. 



The shaping of scion grafts or bud grafts in the 

 field consumes valuable time and I have experi- 

 mented with watery solutions which would allow us 

 to shape scions in the spare hours of evening in 

 preparation for the following day's work, something 

 which would serve as a harmless fluid medium in 

 which the shaped grafts could be carried to the field 

 in quantity. My original idea was to find something 

 similar to what is called physiologic salt solution as 

 employed in animal surgery. Animal tissues for 

 grafting purposes may be kept in salt solution with- 

 out appreciable change for several hours or days pro- 

 tected against microbic attack by the enzymes of 

 their own uninjured cells. This principle could not 

 be applied in its entirety to tree surgery for the rea- 

 son that the salts, sugars, and organic acids in dif- 

 ferent species of trees vary so widely that no one 

 constant isotonic solution can be made to fit all 

 species. Professor C. C. Curtis, of Columbia Uni- 

 versity, suggested the employment of potassium 

 chromate (not bi-chromate), beginning with a one- 

 tenth of one per cent solution and working the other 

 way until a strength was reached that would keep out 

 microbes and at the same time not injure the plant 

 cells of the cut surfaces of prepared grafts. I found 

 that this practically would allow us to shape scions 

 in the evening for use next day, keeping them im- 

 mersed in the solution afterward, yet there appeared 



