338 Plant Physiology 



species which are known to be difficult to force into 

 activity. In this test there were employed several species 

 of Acer, Alnus, Azalea, Castanea, Cornus, Cratsegus, 

 Fraxinus, Populus, Quercus, Tilia, and Ulmus, besides 

 many genera represented by a single species. Shoots from 

 these plants were brought into the greenhouse at Halle, 

 Germany, from December 8 to 23. The preceding table 

 indicates the result of the etherization processes, and also 

 compares this method of forcing with others involving 

 change of conditions. 



198. The effect of etherization. - There are as yet no 

 such definite indications as will permit a competent expla- 

 nation of the effects of etherization upon the plant. By 

 some the treatment is assumed to cause a stimulation, 

 and no further suggestion is made. The view is also ad- 

 vanced that there is an indirect effect upon the stored 

 food. Again it is assumed that there is a loss of water 

 from the cells, equivalent to a considerable time factor in 

 the general maturity process. There is apparently no 

 experimental work to confirm this view, and no ordinary 

 method of desiccation is so promptly effective. It is 

 more probable that the permeability of the protoplasm is 

 directly influenced. 



199. Forcing by immersion in warm water. - In order 

 to start into more rapid and certain growth dormant stock 

 for transplanting, it has long been the custom w r ith some 

 gardeners to immerse the roots in warm water. Recently 

 Molisch has reported many interesting experiments based 

 upon a practice of forcing by means of warm water. 

 The method is applicable to most plants commonly ether- 

 ized, such as lilac, mimosa, Forsythia, and bulbs. He has 



