102 THE MICROSCOPE AND ITS LESSONS. 



the front surface of a hemispherical vitreous body, with- 

 out sinking into it. The space between this body and 

 the sides of the lens forms a ring-like channel which is 

 filled with an aqueous humour, and into this projects a 

 circular process of the thick pigment-coat, which corre- 

 sponds to the choroid, thus defining the pupil of the eye, 

 and at the same time confining the lens to its proper 

 situation. The margin of this pigment-ring may be con- 

 sidered as an iris, and is of various colours, as red, green, 

 or brown, which are active by daylight, while, at the 

 lack of the eye, it is black. 



Now do just reflect again at the important lesson taught 

 us here. Those spiders which hunt in the light of day 

 have their eyes fashioned according to their necessities, 

 while those who hunt at night have an altogether different 

 adaptation to their varying instincts. Does not this 

 suggest to us something beyond an "acquirement"? The 

 black pigment found in day-hunting spiders does for the 

 spider what the pigmentimi nigrum (black pigment) in 

 your eye and mine does for us ; that is, exactly what the 

 black pigment in the camera of the photographer does 

 for him suggestive of the idea that the eye acts like a 

 photographic camera, namely, absorbs the superfluous 

 pencils of light after they have made their impression of 

 the outer object brought to the " sensitized " surface both 

 of the eye and the camera ; but were the same structure 

 observed in the eyes of such spiders as usually hunt at 

 night, that is in the dark, where would they be? So, 

 what do we see in night-hunting spiders' eyes ? Why, a 

 luminous curtain reflecting a bright metallic lustre, 

 making them glare in the darkness like those of cats, 

 whose eyes they resemble. 



Surely here is clear evidence of creative wisdom, and 

 not merely of a " fortuitous concourse of atoms." What 



