38 DISEASES OF DOGS. 



CAITCER. — Tills is a disease which can only be with certainty 

 distinguished and safely treated by the professional man. Fortu- 

 nately, however, It is not of very frequent occurrence In the dog, 

 and many authorities doubt the existence of true cancer in the dog. 



CAI7ZNE XADNHaS.-See Eabies. 



CANKERED MOUTH.— -See Mouth, Cankee op 



CAITEEB OF THE EAK.— <S'ee Eab, Cakkeb of. 



CATARACT. — Cataract consists of the presence in the interior 

 of the eyeball of a whitish opaque spot, which gradually enlarges 

 and very often ends in blindness. This opaque spot is situate on 

 the crystalline lens. It frequently follows ophthalmia, but it may 

 be the result of inflammation or of a wound or blow. It is com- 

 monest ia aged dogs, and is then an evidence of failing health, 

 and the probable breaking up of the system. 

 Nothing short of an operation is of any avaU. 



Fig. 10 is the crystalline lens and is the 



seat of cataract. It is made up of concentric 



laminse, and when hardened, by immersion in 



alcohol, it can be peeled in the same way as 



the layers of an onion can be removed. It is 



composed of a capsule and lens : if the cataract 



is situated upon the lens, it is known as a 



Fig. 10. Crystalline lenticular cataract, but if confined to the cap- 



Lens, showing the , ., . , , i 4. -D iU 



Layers 1, 2, 2, 2, sule it is known as capsular cataract. Uotn 



structures may however be involved, when it 

 is known as capsule lenticular. The hardest portion of the lens 

 is that most centrally placed. 



CATARHH, OB COLD IN THE HEAD.— Dogs that 

 live in freedom, although much exposed to changes of temperature 

 and weather, are not so liable to attacks of catarrh as the more 

 delicately reared, in whom a sudden change from the close atmo- 

 sphere of the room to the open air, or exposure to a drenching shower, 

 frequently produces cold. The first symptoms are shivering and 

 evident languor, succeeded by a hot, dry nose, with a thin discharge 

 at first, but which gradually thickens. If the disease proceed, a hot 

 skin, dulness about the eyes, with other evidences of fever, follow, 

 according to the severity of the case. There is more or less dis- 

 charge from the nose, sometimes accompanied with sneezing ; and if 

 severe, and the bronchial tube be affected, a cough wiU be the result. 

 It is pretty well understood, when applied to ourselves, that a cold 



