THEIR LIMITS AND THEIR FALLACIES. 321 



in the ears, real noise being absent, and the ventriloquist 

 can cheat us just when he will. Still, this sense is less de- 

 ceptive than vision. 



From the sense of hearing we naturally pass on to that 

 of seeing vision; the two being nearly allied. This holds 

 good, whether with Newton we adopt the opinion that light 

 is the result of minute particles darted away from luminous 

 bodies (a theory nearly obsolete) ; or whether we accept the 

 undulatory theory, as it is called, based on the assumption 

 that light consists of waves propagated through a certain 

 very attenuated medium called ' ether.' Adopting the second 

 theory, then will the close analogy between the phenomena 

 of light and sound be too obvious for comment; but if the 

 former the Newtonian theory the connection between 

 the two will not be so apparent. To make it obvious, how- 

 ever, I need merely remark, that optical theories do not 

 affect optical ratios. Whatever theory of light be chosen, 

 the ratios of colours to each other are well ascertained and 

 immutable. 



As concerns the perception of light, the demonstration is 

 almost absolute, that a special organisation, the eye, is in- 

 dispensable. I say almost, for two reasons of diverse origin. 

 First, mere regard for logical sequence will never warrant 

 the naturalist in affirming conclusively that a creature low 

 in creation cannot have any appreciation of light because it 

 has no eyes. The postulate is not beyond all credibility, 

 that mere surface relation of the skin of those animals with 

 luminous emanations may constitute a sort of inferior seeing 

 power. 



The other reason is adduced as a pure matter of defer- 

 ence to those amiable but impressionable ladies and gentlemen 

 ladies mostly the mediums, the clairvoyants and clair- 

 voyantes. If what they allege be true, why, then it stands 

 to testimony that some people can see with their fingers 

 ay, and other parts too, with dorsal and glutasi muscles, for 



Y 



