Cell-Theory not Sujfieient for Explaimng Orgnrusm 1«S1 



on their face are little concerned about cells, there lies an 

 abiding faith in the cell as the *'key to all ultimate biological 

 problems," those of regeneration with the rest. An ilhnn- 

 inating instance of this came out some thirty years ago, 

 before the period in which regeneration was the "firing line" 

 for elementalist biology. I refer to Vochting's attempt to 

 explain a great range of phenomena in plants by the polarity 

 of the plant's cells. This investigator's speculations were 

 based quite as much on his observations on grafting as on 

 regeneration, he having studied this subject along with re- 

 generation and normal development for the purpose of gain- 

 ing light on development in general and on still larger 

 biological questions, rather than for ordinary horticultural 

 purposes. In observing the result of grafting pieces of 

 roots on branches and of branches on roots, of reversing 

 the ends of grafted pieces, and of manipulating the grafts 

 in several other ways, he was greatly impressed by the 

 persistence with which the grafted pieces maintain their 

 characters. The resemblance in several respects of these 

 plienomena in organisms to those of the magnet led him 

 to make the utmost possible of the resemblance. 



Morgan's summary of Vochting's speculation so far as 

 this concerns the cells may be quoted: "The properties of 

 the tissue-complex rest, in last analysis, on that of the 

 cells ; the properties of the whole being only the sum total 

 of the properties of its elements, so that we may say that 

 every living cell of the root is polarized, not only longitudi- 

 nally, but also radially ; each has a different apical and 

 root pole, a different anterior and posterior pole, and also 

 right and left polar relations." ^ 



The conception of polarity in plants and animals, which 

 has had a conspicuous place in later hypotheses of the pro- 

 duction and regulation of form, has by no means been re- 

 stricted to discussions in which cells have occupied the 

 center of interest; so this is not the place to present it 



