VIII. PROBLEMS OF ORGANIZATION 



BY J. S. NICHOLAS^ 



The mystical haze that often surrounds the word 'organization' has no 

 place in science. . . . Particulate units at any level are not wholly inde- 

 pendent of one another. The relations of the particles are part of the 

 system and it is their behavior in relation to one another that constitutes 

 'organisation.' These relations are amenable to experimental investiga- 

 tion and are usually expressed in some kind of configuration. . . . No 

 particle or unit can he clearly understood or its behavior predicted 

 unless its reactions with others are taken into consideration. 



— HARRISON, 1940 



IN the many years during which descriptive and experimental inves- 

 tigations have been carried out in the effort to elucidate the steps 

 by which the developing egg gives rise to the structures of the 

 adult there has been little change in the formulation of the main prob- 

 lems of organization. The attention of the embryologist is still largely 

 focused upon the questions arising from the investigation of the prob- 

 lems of localization, differentiation, polarity, movements of parts and 

 the interaction of tgg components. 



His's expression of the dominant problem of his period, the localiza- 

 tion of parts in the ^gg, has developed into the newer aspect of the 

 localization of potencies for the development of these parts, and also 

 the changes that may be brought about by modifying the interaction of 

 such potencies. This may be on any level of organization whether it is 

 in the cellular layer or even at the tissue level. The movements of parts 

 and the mechanism responsible for cell and layer migrations forms an 

 important phase of the present approach to the fundamental problems 

 given above. 



The problems of organization remain as expressed in the last century, 

 the expansion and methodological approach to those problems has 

 changed markedly and the concepts of the past have undergone radical 

 change in response to the present experimental approach. Some of the 

 changes in concept concern the ideas of the integrity of the cell as a 

 functional unit, while chemically the molecular level has evolved as 

 a biophysiological unit and physically the atom with its association of 

 electrons has come into being. Embryologists are still engaged with 



1 Osborn Zoological Laboratory, Yale University. 



