constitute the act of memory. 1 We may compare these 

 records to the markings left on the tin-foil by the needle of 

 the phonograph, or to the characteristic forms in which the 

 constituent particles of different substances arrange them- 

 selves in the act of crystallisation. Use whatsoever illustra- 

 tion we may, the fact to recognise is that some change takes 

 place, and that a certainly immeasurably minute portion a 

 molecule, or a series of molecules of the brain is cast in a 

 special form by every act of brain function ; and being so 

 left, remains the register or record of the impression, the 

 thought, or the impulse by which it was produced. Two 

 obvious inferences result from this explanation. First, there 

 must be a limit to the brain-work possible in a lifetime. 

 The mass of available molecules may be inconceivably vast, 

 but it is certain that a period will arrive when every page, so 

 to say, will be occupied, and then the brain will neither take 

 in nor give out anything new. Secondly, no thought, or 

 word, or feeling, can be unimportant or without its influence 

 on the mind and character, because it leaves an indelible 

 record behind. 2 



If we bear in mind that as in the physical, so also in the 

 mental world, nothing is lost or perishes nothing that exists 

 can ever cease to be we may perceive that the phenomena 

 of memory are capable of being explained by the great uni- 

 versal law of indestructibility of force of the conservation 

 of energy ; nay, more, the production of the phenomena of 

 consciousness is shown by the physiological study of percep- 

 tion to be subject to the law of the transformation of force. 

 As to what it is that survives our perceptions and ideas, it is 

 difficult to determine ; but as it may be assumed that " every 



1 Smee. 



2 Dr. Mortimer Granville. 



