ttro 



injury to the plant. Solutions of rubber in gasoline 

 and other solvents, and similar "rubber- cements" were 

 found, as was expected, to be injurious to the tissue 

 of the stem. Glue, gelatine and similar hydrophillous 



colloids were found to draw water from the stem and be- 







c»me soft and liquid, permitting easy blov;ing-out of the 



seal. Parafine, and various parafine-vaseline mixtures, 

 as, for instance, the mixture of Briggs and Shantz,-*- 

 would not maintain permanent contact with the stem 

 but would crack away from it, allowing gas leakage through 

 the space thus formed. She problem was solved by means 

 of a seal of grafting-wax applied as shown in section 

 in figure S. A collar of sealing-wax is first built 

 up around the stem for about 1 centimeter (.4 inch) 

 above the tin top. This collar is in the form of a 

 cylinder resting on the tin top and with its inner sur- 

 face about 3 to 4 millimeters from the plant stem. Its 

 actual diameter, as well as the diameter of the hole 

 below it in the supporting tin top, will depend on the 

 diameter of the stem of the plant which is being sealed. 

 The sealing-wax of this collar is applied in very 

 viscous condition and great care must be taken not to al- 

 low it to flow inward and touch or burn the stem. After 

 it is applied its outer edge must be sealed down to the 



1. Bot. (Jaz. 51: 210-2iy (lyil). 



