vi] FIXITY OF POSITION IN PLANTS 83 



less degree during active life, and that " still life," as 

 applied to them, is in point of fact a contradiction in 

 terms. 



Nevertheless there is an underlying truth in the 

 old distinction between animals and plants, though it 

 applies only in a rough sense to the higher terms of 

 the two series. Fixity of position is the common lot 

 of the higher plants just as an ambulatory habit is 

 the rule for the higher animals. I propose, on the 

 one hand, to examine the circumstances which may 

 have led to the adoption of the fixed habit in plants, 

 and on the other to point out certain disabilities 

 which it imposes upon them. These have had to 

 be overcome before success could be assured among 

 the thronged life which subsists on the earth's 

 surface. 



It is through the study of nutrition and mechanical 

 construction that the circumstances are to be sought 

 which have led to the adoption of the fixed habit by 

 plants. The two kingdoms differ widely in their 

 methods ; for while animals take their organic supply 

 at second hand, absorbing in some form or another 

 material already elaborated from its inorganic sources, 

 capturing it, and ingesting it often in bulk ; plants 

 go direct to those inorganic sources, and elaborate 

 their food themselves, absorbing its materials always 

 molecule by molecule. One consequence of this fun- 

 damental difference in the method of nutrition is that 



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