774 OF THE ORGANS OF THE SENSES, AND THEIR FUNCTIONS. 



other's proximity, each approximating to the hue of the complementary 

 color of the other; so that instead of 



A B C D 



red red blue blue, 



we shall see 

 A B C D 



red orange-red greenish-blue blue. 



In the experiments of Manclelstamm, 1 it was found that the acuteness of 

 perception of the eye for slightly different shades of color was greatest in 

 the yellow spectrum, and then successively less in the blue, green, indigo, 

 and finally in the red, in which it was least. 2 Lamansky 3 finds that the 

 sensitiveness of the eye for color is greatest in the order green, yellow, and 

 blue, and least for red. With faint illumination blue is better seen than red, 

 and green and yellow than blue. In commencing atrophy of the optic nerve, 

 red color blindness first appears. Lamansky finds the time requisite for the 

 reception of red three times greater than that for blue. Kunkel, however, 4 

 states that the order of rapidity of perception is, red (0.0573 sec.), blue 

 (0.0916 sec.), and green (0.133 sec.). The time requisite for distinct vision 

 of a line is extremely brief. From experiments with the Electric Spark, 

 O. N. Rood 5 estimates it for a black line at not more than four billioutlis of 

 a second. The means by which differences of color are recognized are at 

 present unknown. Young suggested that there might be different nerves, 

 each having the power of discriminating one of the fundamental colors, but 

 the structure of the Retina gives no support to this view. The laminated 

 structure observed by Max Schultze in the proximal extremities of the rods 

 and cones may possibly have some relation to this power, for if the laminae 

 possessed a different refractive power in the several rods and cones, they 

 would only transmit light of a certain color. 



630. The observations of Schultze seem to point clearly to the conclusion 

 that the perception of colors is due to the cones and not to the rods, for not 

 only is the fovea centralis of the human eye, where cones alone are present, 

 the part most acutely sensitive to variations of color, but in animals of noc- 

 turnal habits like the owl and the bat, no cones are discoverable, and we may 

 conclude that vision in them is reduced to the quantitative perception of 

 light ; or, in other words, to the differences between shades of light and 

 darkness. A simple experiment shows that our notions of color are, like 

 those of temperature, relative and not positive, for although when a pair of 

 smoked glasses are worn before the eyes, surrounding objects at first appear 

 strongly tinged with their color, very short experience enables the wearer to 

 distinguish between different colors, and he sees or seems to himself to see 

 white objects of a fine white color, until he undeceives himself by removing 

 them. 



631. Upon the properties of the Eye in regard to Color, are founded the 

 laws of harmonious coloring, which have an obvious analogy with those of 

 musical harmony. All complementary colors have an agreeable effect when 

 judiciously disposed in combination; and all bright colors, which are not 

 complementary, have a disagreeable effect, if they are predominant : this is 



1 Archiv f. Ophthalmol., Bd. xiii, Abtheil. ii, p. 399. 



2 A remarkable phenomenon of recurrent vision is described by Prof. Young in 

 Amor. Journ. of Sei., vol. iii, No. 1(1. 



3 v. (iriifo's Art-hiv, Bd. xvii, p. 123. 



4 Lond. M.-d. li.-oord, 1874, p. 710. 



6 American Journ. of Science and Art, ser. 3, vol. ii, p. 159. 





