THE ORGANIC AND THE INORGANIC 319 



race or stock, or the activities of the organism in the 

 midst of an ever-changing environment, or even the 

 reactions of the functioning gland, fail, then we seem to 

 be forced to postulate an elemental agency in nature 

 manifesting itself in the phenomena of the organism, 

 but not in those of inorganic nature. This argument per 

 ignorantium possesses little force to many minds : it 

 makes little appeal to the thinker, or the critic, or the 

 general reader, but it is almost impossible to over- 

 estimate the appeal which it makes to the investigator, 

 as his experience of the phenomena of the organism 

 increases, and as he feels more and more the difficulty 

 of describing in terms of the concepts of physics the 

 activities of the living animal. 



We may, however, attempt to illustrate mainly by 

 analogy what is meant by Driesch's entelechia, a more 

 precise concept than is Bergson's elan vital. We return 

 to the consideration of the behaviour of the embryo at 

 the close of the process of segmentation. The organ- 

 ism at this stage consists of a number of cells organically 

 in continuity with each other, either by actual proto- 

 plasmic filaments or by the apposition of parts of their 

 surfaces, thus constituting ' semi-permeable ' mem- 

 branes. These cells are all similar to each other, both 

 structurally and functionally. It does not matter that 

 modern speculations on heredity describe them as 

 unlike in that each contains a different part of the 

 original germ-plasm which had been disintegrated 

 in the process of the division of the ovum and the first 

 few blastomeres ; and it does not matter that these 

 hypotheses are compelled to assume that a part of the 

 original germ-plasm remains intact, being destined to 

 form the gonads of the adult animal. These are hypo- 

 theses' invented to account for the differentiation of 

 the embryo in terms of eighteenth-century physics and 



