5 2 Heredity, 



internal relations are at last structurally registered in harmony 

 with the external ones ; and so conscious memory passes into 

 unconscious or organic memory.' l 



n. 



The foregoing remarks are all within our subject, though they 

 may not seem so ; for, having now referred memory to habit, we 

 will endeavour, in the conclusion of the work, to refer heredity 

 also to habit, and to show that both are but one form of the 

 universal mechanism of that inflexible necessity which rules the 

 world of life and even of thought, and of which memory itself is 

 but one aspect. Without forestalling this conclusion, of which the 

 value can only be appreciated when we have first studied the facts, 

 the laws, and the causes, heredity may at least be compared with 

 memory. Heredity, indeed, is a specific memory : it is to the 

 species what memory is to the individual. Facts will hereafter 

 show that this is no metaphor, but a positive truth. If these con- 

 siderations seem too theoretical, it must be at least admitted that, 

 memory being as closely and perhaps even more closely connected 

 with the organism than any other faculty, the heredity of memory 

 is implied in physiological heredity. Some recent authors, among 

 them Dr. Maudsley, attribute a memory to every nerve-cell, to 

 every organic element of the body. ' The permanent effects of 

 a particular virus, such as that of variola or of syphilis, in the 

 constitution, show that the organic element remembers, for the 

 remainder of its life, certain modifications it has received. The 

 manner in which a cicatrix in a child's finger grows with the 

 growth of the body proves, as has been shown by Paget, that the 

 organic element of the part does not forget the impression it has 

 received. What has been said about the different nervous centres 

 of the body demonstrates the existence of a memory in the nerve- 

 cells diffused through the heart and the intestines ; in those of the 

 spinal cord ; in the cells of the motor ganglia, and in the cells of 

 the cortical substance of the cerebral hemispheres.' a 



Still, when we search history or medical treatises for facts to 



1 Herbert Spencer, Principles of Psychology, 2nd Edition, 2O2. 

 8 Maudsley, Physiology of Mind, ch. ix. 



