212 The Common Cat. [Sess. 



example of a digitigrade animal — that is, it walks on its toes. 

 It is only when it is sitting that it places the whole of its 

 back feet on the ground. What is usually considered the 

 cat's knee is really its ankle. 



The cat progresses either by a grave and stately walk or by 

 a rapid trot. If in a greater hurry, it proceeds by a series 

 of leaps. The sharpness and strength of its claws allow it 

 to climb trees and even walls with ease. A cat can walk 

 over a crowded table without upsetting a single article, 

 because in walking the hind foot is placed exactly in the same 

 spot as that vacated by the fore foot. If you disturb or hurry 

 him, his precision of movement will be destroyed, and so will 

 your treasured articles. 



The cat's eye is perhaps the most remarkable structure in 

 creation. Shakespeare describes it as 



" The cat with eyne of burning coal," — 



(" Pericles," Act III., Prelude)— 



and so it appears if you happen to see the red retina reflected. 

 At other times a green colour is observed, due to reflection 

 from the lens. In bright light, however, the yellow or blue 

 iris contracts, leaving, it may be, only a vertical linear streak. 

 This prevents the light from too acutely stimulating the 

 delicate nerve-endings in the retina, and perhaps injuring 

 them. As the light becomes less intense the iris expands, 

 leaving a vertical elliptic opening, until in obscure light the 

 iris is so expanded as merely to show a narrow ring at the 

 periphery of the lustrous black pupil. At the inner angle of 

 each eye a white membrane is seen. This is the nictitating 

 membrane, common to birds and reptiles, and is called the 

 third eyelid. When a cat is dozing and the eye half open 

 this membrane can be seen partly covering the eyeball. 



The rasping nature of the cat's tongue is due to the large 

 size of the conical papillae upon it. On this roughness 

 depends the power of the animal to clean itself, and also 

 to remove from bones any fragments of flesh which are 

 still adherent. 



Varieties of the Domestic Cat. — Though there are many 

 distinct varieties, the differences do not impose any change in 

 form of the body, but merely in differences of colour or in 



