io6 SCIENCE PROGRESS. 



protoplasm, the actual living substance does not exhibit the 

 property, whilst the same substance when dead does. 

 Clearly then, the admission that protoplasm has a micellar 

 structure, that is, that it is composed of minute and invisible 

 particles consisting of groups of polyatomic molecules, does 

 not involve the admission that there are ultimate vital units, 

 biophors, which reside in the cell-like organisms within the 

 cell-organism. This distinction indeed has already been 

 made and dwelt upon at some length by Weismann (op. 

 cit., pp. 41 and 42). 



It follows then that whilst we may freely admit that 

 protoplasm, and also various inert organic substances, are 

 composed of micellae, and are therefore "organised" in the 

 sense spoken of by von Sachs, we have still to consider the 

 evidence for the existence of biophors. At the outset of 

 this inquiry we meet with a difficulty in that the existence 

 of biophors is assumed by most authors as a means of ex- 

 plaining the phenomena of heredity, and this opens up a 

 wide range of questions into which it is not the purpose of 

 this essay to enter. But it has well been pointed out by 

 Wiesner that if minute vital elements occur at all, those 

 same units which make life possible, and control assimila- 

 tion and growth, must also be the agents in bringing about 

 the phenomena of heredity. This view, which commends 

 itself to everybody, implies that the biophors have only 

 secondarily acquired historic qualities, and that they are 

 primarily concerned in the production of the fundamental 

 processes of life. We may therefore dismiss for the present 

 purpose the complications introduced by heredity and con- 

 fine our inquiry to the functions of biophors as bearers of 

 the essential vital qualities. 



It is urged in favour of a theory of biophors that life 

 must be connected with a material unit of some sort (Weis- 

 mann) ; that function presupposes structure (Whitman), and 

 that the structure necessary for the exhibition of such 

 complicated functions as those of living protoplasm cannot 

 be of such a simple molecular kind even as the micellar 

 structure postulated by von Sachs and Niigeli, but must 

 consist of a definite arrangement, an architecture or organ- 



