HOW SVK SHK. ISI 



nation of till' two sensations of n-d ami Muc. Tlio same 

 liolds triu' for tlir browns, and tho various otlu-r tints of 

 that ordor. TIic coinhination, however, is made in the 

 ln'niii and not in the retina. 



We have now linally traced the ehan<ijes whieh enter into 

 the })roduetion of the fmiction of vision to the brain. If 

 these changes stop anywhere slu)rt of there, we have no sen- 

 sation, no lii^ht. In fact, it is not vision at all, for it is the 

 brain which overrules all. and transforms impressions into 

 thouglit and consciousness. We see — not with the eye — hut 

 with the brain — the eye bein>5 only one of the instruments 

 which the brain uses to bring to it knowledge of the changes 

 whieh tiike place in the outer world. This knowledge it 

 arranges and classifies under the superintendence of the 

 judgment, and we give to it the comprehensive name of 

 vision. This knuls us to wliat was, for a long time, consid- 

 ered the boundary not only of our actual knowledge, but 

 even of legitimate s[)eculation. ("onsciousness was consid- 

 ered not only a terra incitgnitd, but also a Urra sacra, within 

 whose hallowed i)recincts even the boldest materialist dare 

 not venture with his unholy atoms and molecules. But 

 true science is always fearless, and pushes its way with irri- 

 sistable force into ever}' avenue where honest investigation 

 offers for its labor tlie smallest modicum of new truth. 



Anatomical science lias traced, by its numerous and pa- 

 tient di.-^sections, the optic nerve to its termination in a 

 certain portion of the brain. As nothing in the workings 

 of Nature is ever purpo.seless, we are bound to believe that 

 as the nerves always end in the same part of the brain, the 

 lirain in that immediate vicinity mu.st have .some connec- 

 nection with transformation of liglit waves into vision. 

 Then the vivisi'ctionist came forward with that knife, whose 

 supposed cruelties have been so elo<[Uently sung by a thou- 

 sand sentimental tongues, and lemoved that particular {»or- 

 tion of the brain from the living creature, and the animal 

 became completely blintl. Thus one more stone of trutii 

 was added to the slowly growing temple of human knowl- 

 edge, and to-day every physiologist will tell you that the 



