n6 SCIENCE PROGRESS. 



altogether absent and yet the life processes go on un- 

 changed. 



It must be confessed then, that the experiences which 

 so amply justified our generalisation when applied to com- 

 posite organisms are altogether lacking when we seek for 

 a justification for applying it to the simplest unicellular 

 organisms. Moreover I have just shown that in one im- 

 portant particular at least, we do not merely lack these 

 experiences, but that we have experiences of an entirely 

 different kind. In face of this is it not obvious that the 

 captivating generalisation must be abandoned altogether in 

 the region which we are now discussing ? For it is founded 

 on experience, and where experience fails or is contradictory 

 the generalisation fails also. 



After what has already been said it is unnecessary for 

 me to enter into a detailed examination of the other state- 

 ment which is considered to mark a great advance in bio- 

 logical thought, that "the cell is an organism". It is 

 sufficient to say that if this proposition means anything at 

 all, it means that the cell has an organisation which is 

 similar in kind to that of a composite organism of which a 

 cell is a part. If I am told that it does not mean this, but 

 something else, then I ask, firstly, what does it mean ? And, 

 secondly, if it does not mean this, what necessity is there for 

 assuming that the protoplasm of the cell is built up of bio- 

 phors, the biophor being the elementary living constituent, 

 assimilating, growing and dividing, taking up definite posi- 

 tions in the cell, combining with others like or unlike itself to 

 form higher aggregates, and so impressing a fixed archi- 

 tecture on the cell of which it is a component ? Why, in 

 short, if the statement does not mean that the organisation 

 of the cell is the same in kind as the organisation of a 

 composite animal, why then does everybody who believes 

 that the cell is an organism ascribe to it an organisation 

 which is the same in kind as that of the higher animals ? 



The fact is, and it is patent to everybody, that most 

 authors do conceive of the cell-organisation as being the 

 same in kind as the organisation of higher animals. They 

 either have the courage of their opinions, like Wiesner, 



