130 ANIMAL MECHANISM. 



The writer remembers an accomplished female albino, 

 who publicly exhibited herself in Boston, several years 

 since. An exact wax figure of the lady with the 'red 

 eyes,' belongs to a group, now in exhibition at the New 

 England Museum. About the same period, the writer 

 also recollects of seeing a white negress, who was an al- 

 bino. Her father and mother were of the jet black color, 

 though she had a pale, deadly white complexion. The 

 hair of both these albinos was silky and milk white. 



THE REASON WHY MANY ANIMALS SEE IN THE DARK. 



Owls, fishes, cats, bats, &c, instead of the pigmentum 

 nigrum, have a silvery paint of a metallic lustre, where 

 others have the black paint, which operates like a mirror, 

 in reflecting the light from point to point, within the eye, 

 illuminating it till its concentration excites the retina to 

 perceive. When viewing a cat's eyes in the remote part 

 of a dark room, there are certain positions, in which they 

 are seen by the observer, by the reflected light within 

 themselves, as though they were phosphorescent : their 

 brilliancy is very peculiar. Upon the principle of a look- 

 ing-glass behind the retina, all the night-prowling animals 

 are qualified for seeing with those few rays of light, 

 which the constitution of their eyes is formed for collect- 

 ing in the dark. By daylight, they perceive objects, 

 as man does in the dark, viz. indistinctly. Nature is 

 remarkably economical in the use of matter which enters 

 into the composition of animal bodies. If a man be kept 

 a long time in a perfectly dark room, the pigmentum 

 nigrum is taken away; but a compensation is given him, 

 for he can then see as perfectly in the dark, as he could 

 before in the light. On the other hand, the paint. is de- 

 posited again when he is restored to the light of day. 

 This point has been decided in the persons of state pris- 

 oners kept in the dungeons of European despots. 



Is there any arrangement in the eye, and what is it, by 

 which animals that see in the dark are enabled to make 

 up for the want of external light ? When we consider 

 the metallic lustre of the tapetum, which in many animals 

 occupies a great part of trie choroid coat, or even its 

 whole surface ; farther, its resemblance to a concave 

 mirror, and its relation to the light that penetrates into 



