SMELL, TASTE, AND TOUCH. 



eyelids then be closed, a blue spectrum of the sun will be seen, 

 and will continue to be visible until the retina recover its state 

 of repose. 



If we write a page or two with red ink, and then commence 

 to write with black ink, the writing will appear of a light blue 

 colour, and will continue to appear so until the retina loses the 

 impression made by the red ink upon it. In passing, however, 

 from the black to the red, no illusion is produced, the black not 

 acting on the retina so as to excite it. 



If small holes be made in a red curtain, so as to admit the 

 rays of the sun through them, the light which will be thrown 

 upon a sheet of white paper will be the general redness produced 

 by the semi-transparency of the curtain, with the white spots 

 produced by the lights passing through the holes ; but these 

 white spots will appear to the eyes blue. 



It will appear, from these observations, that effects are pro- 

 duced by the juxtaposition of colours in objects of art independent 

 of the separate properties of the colours themselves. Two 

 colours, when seen in juxtaposition, do each of them appear to 

 the eye different from what either would appear to be if seen 

 separately from the other. 



6. The senses of smelling, tasting, and even of feeling or touch, 

 are liable to innumerable causes of deception. If the organ at 

 the time it receives an impression be in any unusual condition, 

 or even out of its usual position, the indication of the impression 

 will be fallacious. 



If two fingers of the same hand, being crossed, be placed upon 

 a table, and a marble or a pea is rolled between them, the impres- 

 sion will be, if the eyes are closed, that two marbles or two peas 

 are touched. 



If the nose be pinched, and cinnamon be tasted, it will taste 

 like a common stick of deal. This is not a solitary instance. 

 Many substances lose their flavour when the nostrils are stopped. 

 Nurses, therefore, upon right and scientific principles stop the 

 noses of children when they give them doses of disagreeable 

 medicine. 



If things having different or opposite flavours be tasted 

 alternately, in such rapid succession as not to allow the nerves 

 of tasting to recover their state of repose, the power of dis- 

 tinguishing flavour will be lost for the moment, and the sub- 

 stances, however different, will be undistingnishable from one 

 another. Thus, if the eyes be blindfolded, and buttermilk and 

 claret be alternately tasted, the person tasting them, after a few 

 repetitions of the process, will be unable to distinguish one from 

 the other. 



S7 



