the etherization of pl.^nts. 71 



Season of Treatment. 



Generally speaking all hardy plants of northern climates have 

 a well-defined rest period which is usually designated as the dormant 

 period. During this season of rest the protoplasm of the cell is in 

 a more or less complete quiescent condition. Johannsen has very 

 ingeniously divided this season into three periods which he very 

 appropriately designates as the "Bef ore-Rest," "Central-Rest," 

 and "After-Rest." The first period of repose is defined as that 

 immediately following the formation of flower and leaf buds ex- 

 tending from June to September. The second period which is 

 shorter includes September and about three-fourths of October. 

 The after rest period begins the latter part of October and extends 

 into December and under certain conditions into January. Accord- 

 ing to Johannsen's observations the most marked effect from 

 etherization is obtained from treatments made during the first and 

 last rest periods. The central period being the season of deepest 

 rest it is more difficult to create an impression upon it by etheriza- 

 tion. Less marked results may be expected toward the close of the 

 third rest period than the beginning of it. Of course any di\asion 

 of the period of rest in plants must be of a more or less arbitrary 

 nature. Unseasonal climatic conditions exert such a marked 

 effect upon plant growth as to materially change the first and second 

 rest periods. Such variations must of necessity be taken into 

 consideration by the forcer of plants. 



Theoretical Action of Anesthetics. 



The earlier investigators Bernard (4) and Dubois (8) were of the 

 opinion that anesthetics produced much the same effect upon 

 plants as upon the higher forms of animal life, rendering them 

 insensible to outward stimuli and also extracting water from the 

 cell protoplasm in many respects similar to its action upon blood 

 in animals. This latter phenomena does not differ materially from 

 the action of frost upon plant tissues and indeed its effect was 

 likened to that of frost by these two investigators. Johannsen (15) 

 believed that its action caused a sudden cessation of all plant 



