and of several other Animals. 301 



and the badger, of a pure white, edged with blue. This colour- 

 ed part of the Ruyischian membrane is named the Tapis. Birds 

 have it not *.^ 



We see from this description, that the eyes of animals which 

 do not shine like those of cats, have no tapis, or have it only 

 of a dark colour. The eye of man does not shine, or only 

 shines in a very slight degree -f-. I have often tried to ascertain 

 whether it does, and in the most favourable circumstances have 

 only at the most perceived an extremely feeble and doubt- 

 ful light. I have never seen the eyes of hogs, rabbits, or 

 hares, which have the tapis of a chocolate brown, emitting 

 light ; while I have very frequently seen the eyes of sheep, oxen, 

 and horses, sparkle with the most lively colours. I have often 

 had nocturnal birds at my disposal, and have often observed 

 them, but without ever seeing their eyes shine like those of cats ; 

 and Spallanzani, who made numerous experiments upon these 

 animals, and who examined them with reference to this subject, 

 by night, by day, and during the twilight, both captive and in 

 a state of liberty, never remarked either that their eyes were 

 susceptible of shining in the dark, with that sort of lustre which 

 he imagined to be phosphoric. It is true, that the tapis of the 

 dog does not agree with the colour of the shining of its eyes ; 

 but this colour may be modified by that of the crystalline hu- 

 mour, or of some of the other humours of the eye. 



It is astonishing that M. Ciivier, after this description, does 

 not say a word of the phenomenon of which the tapis appears to 

 me to be the cause ; but this celebrated anatomist, whose genius 

 knows to subject itself to the laws of a rigorous accuracy, not 

 having probably observed it himself with sufficient care, has ra- 

 ther chosen to say nothing, than to repeat the opinions of others 

 respecting a subject which, at bottom, belongs much less to ana- 

 tomy than to Natural History. 



M. Dessaignes not only says that the eyes of certain animals 

 kindle and appear as if on fire in the dark ; but, according to him, 

 they owe this faculty to the expansive effect of the lively passions 

 with which the animal is affected. But he is certainly deceived, 



* Cuvier's Lejons. d'Anat* Comp. t. ii. p. 397, 402. ^ 



•f- This luminous property we have remarked in eyes of several individuals, 

 principally females Ed. 



