Il8 THE PLANT WORLD. 



rises abruptly and becomes very strong ; and with the decrease in 

 temperature thereafter it continues to rise gradually but very 

 much less rapidly than at first. The result is that when tissue 

 freezes a very large quantity of water is abstracted at the start 

 to form the first particles of ice, but with each degree of fall in 

 temperature thereafter only a very small quantity is lost by the 

 cell. This quantity becomes less and less with each degree, since 

 the imbibition force increases at a more rapid rate than the force 

 of crystallization."^ 



In conclusion, then, it may be said that the water comes out of 

 the cell during freezing either through the equalizing action of 

 the force of imbibition following the abstraction of water by the 

 crystal from the surface film lining the intercellular space, or 

 through the pulling action of the ice crystal at the end of minute 

 but possibly rigid columns of water which extend into the cell. 

 Until the rigidity of this capillary water is demonstrated the 

 former method is the more probable. The extrusion of water by 

 the protoplasm of certain plants at low temperatures can be con- 

 sidered only as an accidental, not a necessary, phenomenon as far 

 as the freezing process is concerned. 



Botanical Symposium. — The third annual meeting of the 

 Botanical Symposium will be held from July 2d to 9th, 1906, at 

 Mountain Lodge, Little Moose Lake, Old Forge, N. Y. Through 

 the courtesy of the members of the Adirondack League Club the 

 privilege of occupying the club house for one week is extended 

 to the members of the Conference. Tickets should be bought 

 to Fulton Chain Station on the Adirondack Division of the N. Y. 

 C. & H. R. R. Single fare from Xew York City $6.46. Board 

 $2.50 to $3.00 a day. Stages will meet the party at Fulton Chain 

 Station. Those expecting to attend are requested to notify Mr. 

 Joseph Crawford, Secretary, 2824 Frankford Avenue, Philadel- 

 phia, Pa. 



* Cf. Sachs' " Lelirhuch," and Muller-'rinirgau's work for accounts of 

 the physics of freezing, in the main sinnlar to the one here given. 



