SUMMARY AND CONCLUSION 



All the phenomena of heredity depend on minute vital units 

 which we have called ' biophors/ and of which living matter is 

 composed : these are capable of assimilation, growth, and mul- 

 tiplication by division. We are unacquainted with the lowest 

 conceivable organisms, and do not even know if they still exist. 

 But they must at any rate have done so at some time or other, in 

 the form of single biophors, in which multiplication and trans- 

 mission occurred together, no special mechanism for the purposes 

 of heredity being present. A higher order of beings would then 

 have been constituted by those organisms which were composed 

 of a large number of similar biophors. Of these also we have no 

 actual knowledge based on observation, but must suppose that 

 they too required no special apparatus for the processes of 

 transmission ; for a reproduction by binary fission must result 

 in two perfectly corresponding halves, each containing similar 

 biophors, and each of which, simply by the multiplication of 

 these units, is able to give rise to a complete organism exactly 

 like the parent. 



This simple form of transmission must have become modified 

 when the biophors underwent differentiation in connection with 

 a division of labour, and became combined in various ways to 

 form the body of the organism. These two kinds of hypothetical 

 beings might be respectively distinguished as homo-biophorids 

 and hetero-biophorids. Not only might a firmer cortex and 

 softer internal substance be present in the latter, but a differen- 

 tiation into anterior, posterior, dorsal, and ventral regions might 

 occur ; several layers of the body substance, differing structurally 

 and functionally from one another, might also be developed, to- 

 gether with motile and non-motile processes — such as flagella, 

 cilia, spines, and hooks. — like those present amongst the Infu- 

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