162 The Unity of the Organism 



whole, and the apparently composite character which it may 

 exhibit is owing to a secondary distribution of its energies 

 among local centres of action." 



Our only object in this section is to place before the 

 reader as much as practicable of the views of biologists that 

 the organism and not the cells of which it is composed is 

 the main thing in development. It would consequently be 

 put of place to go into a critical examination of this lan- 

 guage. It will, however, be permissible by way of intimation 

 of what will be involved in the discussion, to ask how the view 

 that "the life of the multicellular organism is to be con- 

 ceived as a whole," can be made to tally with the view ex- 

 pressed in the first sentence of The Cell, already quoted, 

 that "the key to all ultimate biological problems must, in 

 the last analysis, be sought in the cell." 5 



Wilson's authority is deservedly so great in all these 

 matters that his utterances will be taken as one of the 

 main centres around which our examination of the cell theory 

 will hover. On this account, I quote somewhat more at 

 length than would be essential to show merely his general 

 position. In the chapter, "Cell-division and Development," 

 he writes : "It remains to inquire more critically into the 

 nature of the correlation between growth and cell-division. 

 In the growing tissues, the direction of the division-planes 

 in the individual cells evidently stands in a definite relation 

 with the axes of growth in the body, as is especially clear 

 in the case of rapidly elongating structures (apical buds, 

 teloblasts, and the like), where the division-planes are pre- 

 dominantly transverse to the axis of elongation. Which of 

 these is the primary factor, the direction of general growth 

 or the direction of the division-planes? This question is a 

 difficult one to answer, for the two phenomena are often too 

 closely related to be disentangled. As far as the plants are 

 concerned, however, it has been conclusively shown by Hof- 

 meister, De Bary, and Sachs that the growth of the mass 



