528 THE POPULAR SCIENCE MONTHLY. 



The discovery has well been called " the triumph of the last 

 place of decimals " that is, of work so exact that the worker knew 

 that the small differences in the figures he obtained must be due 

 to the presence of an unknown substance rather than to an error 

 in his results. The prediction based on this observation, the 

 search for the disturbing substance, and its discovery, form an 

 achievement which, in the history of science, has perhaps only 

 been surpassed by the prediction of Neptune by Adams and 

 Leverrier, and its subsequent discovery by Galle. 







THE NERVOUS SYSTEM, AND ITS RELATION TO 



EDUCATION. 



By JOHN FERGUSON, M. A., M. D., Ph.D., 



TORONTO. 



JOHN LOCKE, the physician and philosopher, long ago said 

 that all our knowledge came from experience. Throughout 

 his Treatise on the Human Understanding he develops this view 

 of the acquisition of knowledge. This was followed by the writ- 

 ings of David Hume, the Scottish historian and metaphysician, 

 who held that we knew nothing of objects in themselves, but 

 only through their qualities; or, in other words, that we know 

 of nothing but ideas. This was in turn followed by Immanuel 

 Kant's Critique of Pure Reason, who took the ground that, though 

 all our knowledge did not come from experience (as taught by 

 Locke), yet it all came by experience. He held firmly to the 

 ground that we had intuitions, or an a priori knowledge. It was 

 this intuitive power that enabled us, by experience, a posteriori, 

 to acquire knowledge of the qualities and of the forms of matter. 

 Later came those who, like Ribot, Spencer, Romanes, have taught 

 that there is no science of mind apart from the operations of the 

 nervous system ; that the operations of the brain constitute what 

 is known as mental processes. Differing from these, the late 

 T. H. Green held, as did Kant, that there is a science of ethics 

 and psychology, independently of the study of physiology. 



Fortunately for the purposes of this article, it will not be 

 necessary to review the opinions of the above writers ; it will not 

 be necessary to prove which of the many views is correct. This 

 much is definitely- known: that certain physiological laws govern 

 the human body, so as to determine what we know and how we 

 came to know it. The intuitions of Kant, the common sense of 

 Locke and Reid, the skepticism of Hume on knowledge, the ideal- 

 ism of Berkeley, need not detain us, as they have no special inter- 

 est for the present. The object before us is to show that we 



