GROWTH AND DECAY OF MIND. 331 



verse, that the industries of all the factories and trading establish- 

 ments in the world are mere indolence, and awkwardness, and un- 

 productiveness, compared to the miraculous activities of which his 

 lazy bulk is the unheeding centre." Yet the conscious thought of 

 the lout remains as unlike as possible to the conscious thought of the 

 philosopher ; nor will crusts of bread or bottles of wine educe aught 

 from the lout's brain that men will think worth remembering in future 

 ages. 



Moreover, we must remember that we have to deal with facts, let 

 the interpretation of these facts be what it may. The relations be- 

 tween mental activity and material processes affecting the substance 

 of the brain are matters of observation and experiment. We may 

 estimate the importance of such research with direct reference to the 

 brain as the instrument of thought, without inquiring by what pro- 

 cesses that instrument is called into action. " The piano which the 

 master touches," to quote yet again from the philosophic pages of 

 Holmes's " Mechanism in Thought and Morals," " must be as thorough- 

 ly understood as the musical box or clock which goes of itself by a 

 spring or weight. A slight congestion or softening of the brain 

 shows the least materialistic of philosophers that he must recognize 

 the strict dependence of mind upon its organ in the only condition of 

 life with which we are experimentally acquainted ; and, what all 

 recognize as r soon • as disease forces it upon their attention, all think- 

 ers should recognize without waiting for such an irresistible demon- 

 stration. They should see that the study of the organ of thought, 

 microscopically, chemically, experimentally, in the lower animals, in 

 individuals and races, in health and in disease, in every aspect of 

 external observation, as well as by internal consciousness, is just 

 as necessary as if the mind were known to be nothing more than 

 a function of the brain, in the same way as digestion is of the 

 stomach." 



In considering the growth of the mind, however, in these pages, it 

 appears to me sufficient to call attention to the physical aspect of the 

 subject, without entering into an account of what is known about the 

 physical structure of the brain and the manner in which that structure 

 is modified with advancing years. Moreover, I do not think it de- 

 sirable, in the limited space available for such an essay as the present, 

 to discuss the various forms of mental power ; indeed, this is by no 

 means essential where a general view of mental growth and decay 

 is alone in question. Precisely as we can consider the development 

 and decay of the bodily power without entering into a discussion of 

 the various forms in which that power may be manifested, so we can 

 discuss the growth of the mind without considering special forms of 

 mental action. 



Nevertheless, we cannot altogether avoid such considerations, sim- 

 ply because we must adopt some rule for determining what constitutes 



