DISEASES OF DOMESTIC ANIMALS. 79 



may be of a tubercular character, especially if there is a tubercular 

 tendency ; but we oftener meet with this in dogs than in other ani- 

 mals. In dogs it is called 



Canker, and is either external or internal, and involves the internal 

 or external flap and the meatus. Canker is more likely to occur in 

 those dogs used for sporting, from running through long grass, brush, 

 etc., getting wet and then drying, which sets up irritation ; and the 

 manner of feeding the animal aggravates it — an over- abundance of 

 animal food making him extremely fat, etc. 



Symptoms. — More or less irritation ; he moves the head from one 

 side to the other ; scratches the ear ; if you look at the ear you may 

 find a discharge of an extremely fetid character. 



Treatment is both local and constitutional. If from a well-marked 

 cause, remove the cause ; cleanse nicely and syringe with tepid water 

 or carbolic acid — one part to twenty or twenty-five of water, or even 

 stronger ; or nitrate of silver in solution ; or the tincture of the chlo- 

 ride of iron ; keep him fixed in such a manner that he cannot shake 

 the head, and if plethoric, give physic, syrup, or buckthorn and jalap, 

 or castor-oil is very good. Aloes may be given, but it is not so good, 

 as it has a tendency to irritate the rectum. Iodide of potassium is 

 also good. If the ear becomes gangrenous, you may have to remove a 

 part of it, and you may have abscesses from some causes ; they are 

 generally serious. Make an incision, and then use some of the reme- 

 dies given. Restrict the diet to a certain extent. Give some exercise. 

 We sometimes meet with fistula at the root of the ear. This is more 

 common in horses, and'is generally congenital, or from malformation. 

 It is easily detected by close examination, but it might be overlooked. 

 But you can notice a little matter at the root of the ear, and a small 

 opening, which is a fistulous opening, and passes well in at the root of 

 the ear, and is often of long-standing. The skin may be reflected in 

 and covered with the ear. Exercise the parts and cut this fistulous 

 wound out. It may not set up much irritation, but must generally be 

 dissected out, or you may inject with caustics and afterward dress 

 with a mild caustic, as nitrate of silver, chloride of antimony, tincture 

 of the chloride of iron ; and you may have tooth-deposits — tooth sub- 

 stances have been formed at the root of the ear and caused fistula ; in 

 such cases you find enlargement to some extent. It is possible that 

 tooth-substances may be found in the testicle. There is scarcely a 

 tissue where a tooth substance may not be found. 



DISEASES OF BONE. 



Osseous, — The diseases of the osseous structures. These hard 

 structures are liable to the inflammatory process, the same as the soft 

 structures, and, according to the character of the inflammation, cer- 

 tain names are applied. Bone is composed of two tissues — the com- 

 pact and cancellated, covered by a vascular, white, fibrous, highly 

 nervous membrane, called the periosteum. If inflammation attacks 

 the internal part of the bone, it is likely to involve the periosteum, 

 and if it attacks the periosteum, it is likely to involve the bone. 



Ostitis. — Inflammation of bone in the horse. This is generally 

 found the result of either direct or indirect injury, but sometimes of 

 a constitutional tendency. It may begin either in the compact or 

 cancellated tissue. The first effect is to increase the size of the hav- 

 ersion canals, which become more irregular in size and outline, and 



