316 NATURAL SCIENCE [November 



equilibrium in the cells and in the whole organism. Owing to this 

 being a labile equilibrium, any disturbance due to an altered 

 condition of the environment will alter the ' set ' of the 

 gemmaria and change the conditions of their equilibrium. It is 

 as the result of their relation to the organism at large that 

 the gemmaria of the reproductive cells E of an organism A are 

 compelled to reproduce the likeness of A ; consequently when the 

 continuance of altered surroundings alters A to A', the gemmaria of 

 the reproductive cells will get a ' set ' changing them to E', which 

 will reproduce the altered organism A'. Now, as a formal hypo- 

 thesis, this serves to give a very pretty provisional explanation of 

 many phenomena of organic life ; but we have no sufficient micro- 

 scopic evidence in its favour, and, to me at least, much that speaks 

 against it. We know too little of the physical relations of cell- 

 life to be able to accept, even provisionally, a theory based mainly 

 on geometrical and mechanical conceptions. 



The most satisfactory explanation, perhaps, is that put forward by 

 Hering and Samuel Butler, 1 the latter of whom has written with 

 singular freshness and an ingenuity which compensates for the 

 author's avowed lack of biological knowledge. This theory has 

 indeed a tentative character, and lacks symmetrical complete- 

 ness, but is the more welcome as not aiming at the impossible. 

 A whole series of phenomena in organic beings are correlated 

 under the term of memory, conscious and unconscious, 

 patent and latent. Our memory is conscious, when we say a 

 lesson or remember a birthday ; unconscious, when we let our 

 fingers play of themselves a piece of music of which we could 

 not write down a note ; patent, when we remember to call at a 

 friend's house ; latent, during the interval while the servant is 

 waiting at the open door, until the sight of the familiar stick in 

 the hall recalls the owner's name which would not recur to our con- 

 sciousness. Of the order of unconscious memory, latent till the 

 arrival of the appropriate stimulus, is all the co-operative growth 

 and work of the organism, including its development from the repro- 

 ductive cells. Concerning the modus operandi we know nothing : 

 the phenomenon may be due, as Hering suggests, to molecular 

 vibrations, which must be at least as distinct from ordinary physical 

 disturbances as Eontgen's rays are from ordinary light, or it may 

 be correlated, as we ourselves are inclined to think, with complex 

 chemical changes in an intricate but orderly succession. For the 

 present at least the problem of heredity can only be elucidated by 

 the light of mental and not material processes. 



Qceen's College, Cork. MARCUS HarTOG. 



1 " On Memory as a Universal Function of Organised Matter" (Vienna, 1870, ex. 

 S. Butler in " Unconscious Memory," p. 97). 



