THE BIOLOGY OF THE CELL SURFACE 



must establish Its philosophy on this basis. Any philos- 

 ophy of biology must take Into account the activity of the 

 superficial cytoplasm. 



The living thing Is part of the natural world; It grows 

 and lives on the stuff of which It Is made and whence It 

 came. Then living thing and outside world constitute one 

 Interdependent unity, as evolution teaches, as the develop- 

 ment of an animal egg reveals. As the boundary, the living 

 mobile limit of the cell, the ectoplasm, controls the Integra- 

 tion between the living cell and all else external to It. The 

 ectoplasm Is the means of exchange for Incoming and out- 

 going substances. It Is keyed to the outside world as no 

 other part of the cell. It stands guard over the peculiar 

 form of the living substance. Is buffer against the attacks 

 of the surroundings and the means of communication with 

 It. 



If we trace the development of the brain In higher ani- 

 mals. Including man, we find that always It arises from 

 ectoderm cells, those cells that possess most ectoplasm. 

 The whole nervous system arises in animals always on the 

 outer surface of the embryo; only later in development does 

 it become enclosed within the body by other cells. Then 

 the functions of the brain represent highly developed general 

 properties of primitive ectoplasm. The brain can not be 

 fully appreciated unless we bear this in mind. As with 

 brain, so with sense organs. 



The origin and development of the brain show that a 

 conception which assumes that either the individual alone 

 or only the outside world is real, has no biological basis. 

 The interdependence between individual and outside world 

 is a postulate which has its sanction not from any abstract 

 philosophical principle, but is true because of the biological 

 basis here set forth. The best system of philosophy, then, 

 Is that which recognizes living thing and outside world as 

 one interdependent continuum. Instead of building our 



366 



