THE! ORGANS OF SPECIAL SENSE. 221 



this is followed by eczeniatous eruption and a drying of 

 serum mixed with blood on the surface, next ulceration 

 takes place and the formation of pus. In neglected cases 

 fungating excrescences grow in the ear, and tend, by 

 coalescence, to obliterate the auditory canal ; the hair 

 becomes matted by discharge, and beneath it sinuous 

 ulcers may form and terminate in very severe ulcerative 

 disease of the face. Occasionally there will be no erup- 

 tion on the skin detectable, simply swelling around the 

 root of the ear, and slight oozing of purulent material, 

 and a little gurgling when the root of the ear is mani- 

 pulated. The causes are accumulation of water in the 

 ear, and (Touatt says) the determination of blood to the 

 head from swimming in cold water; thus it is described 

 as most frequent in water dogs ; it occurs especially in 

 long-eared animals, particularly those which are plethoric, 

 have been confined much and highly fed. Soapsuds left 

 in the ear after washing, accumulations of dirt, and exten- 

 sion of cutaneous irritation in mange also give rise to it. 

 Treatment comprises keeping the patient from water, con- 

 fining his ears by means of a special ear-cap such as will 

 be described shortly, regularly cleansing the parts and 

 dressing them thoroughly with agents adapted to allay cuta- 

 neous irritation and ulceration. Medicaments of an astrin- 

 gent character are preferred. Unguentum calamine is most 

 valuable. A seton in the neck or poll, sometimes recom- 

 mended, will hardly be found necessary except where the 

 mischief is very deep seated. According to the amount 

 of care in dressing the case will be the rapidity of cure. 

 Ooculet's treatment consists in applying a blister over the 

 external surface of the ear by dressing every second day 

 with tincture of cantharides 4£ parts, tincture of galls 1 

 part. This allays itching and causes pain, so the animal 

 ceases to shake his head and the disease soon heals. 



External Canker affects the lower margin of the ear- 

 flaps ; it first appears as an eruption and ulceration 

 rapidly occurs, the skin thickens and the ulcerative change 

 involves the cartilaginous substance. Thus the margin of 

 the ear becomes irritable and swollen, and the disease 



