EPIGENESIS OR EVOLUTION. 113 



quired to form a single cell, is no doubt a probability. Un- 

 less we take refuge in such unmeaning phrases as formative 

 forces, vital principles, and the like, we are obliged to assume 

 some material unit, the basis of the phenomena of life. But 

 we can hardly go as far as Weismann and assert that a par- 

 ticular kind of unit, protean though its constitution may be, 

 his biophor, must exist, and is therefore no mere hypothetical 

 affair, but a reality. To assert this is surely almost as much 

 an error as to assert that no such units do exist. Practically 

 when we have passed beyond the limits of vision we have 

 entered upon the region of the unknown, possibly of the 

 unknowable, and convenient as it may be to have a hypo- 

 thesis which will enable to represent facts to ourselves in 

 an intelligible way, we ought to be very cautious in our 

 statement of the hypotheses. The arguments of those who 

 plead for the existence of infinitesimal units, whether micellae 

 or pangenes or biophors or what not, amount to this : so 

 far we have been able to observe with our senses, but the 

 things which we have observed remain unintelligible to us ; 

 reason tells us that behind all this there must be something 

 which we are at present unable to observe, and analogy 

 leads us to believe that this something is in the form of 

 material particles. Excellent philosophy, but is it physical 

 science ? And if the material units are conceded, is the 

 difficulty as regards vital phenomena in any way diminished ? 

 Is it not simply moved further back? To continue with 

 Weismann's hypothesis, the most complete and the most 

 ably sustained of any that has been put forward : the bio- 

 phors exhibit the primary vital forces, assimilation and 

 metabolism, growth and multiplication by fission ; they are 

 also the bearers of the qualities of cells, by which is meant 

 that each biophor has a quality of its own which it is 

 capable of impressing on the cell of which it forms a part. 

 As each biophor is capable of reproduction giving rise by 

 fission to its like, it hands on the particular quality inherent 

 in it, that is to say, it has heritable qualities, which, how- 

 ever, are not of much importance, since every biophor is 

 isotropic, capable of further change by a rearrangement of 

 its constituent molecules. Truly a protean being, this 



