172 THE SENSE OF SMELL. 



the sinuses of the face and head. It is, however, so mingled with the 

 mucous membrane, that no power of the lens has enabled us to follow it 

 so far. It is like the portio mollis of the seventh pair, eluding the eye, 

 but existing in sufficient substance for the performance of its important 

 functions. 



We have frequent cases of ozcena in old dogs, and sometimes in those 

 that are younger. The discharge from the nostril is abundant and con- 

 stant, and sometimes fetid. The Schneiderian membrane, of more than 

 usual sensibility in this animal, is exposed to many causes of irritation, 

 and debilitated and worn out before its time. Pugs are particularly sub- 

 ject to ozaena. I scarcely ever knew a very old pug that had it not to a 

 greater or less degree. The peculiar depression between the nasal and 

 frontal bones in this breed of dogs, while it almost totally obliterates the 

 frontal sinuses, may narrow the air-passage at that spot, and cause greater 

 irritation there from the unusual rush of the air, and especially if the 

 membrane becomes inflamed or any foreign body insinuates itself. 



Little can be done in these cases, except to encourage cleanliness about 

 the face and nostrils. It is, in the majority of these cases, a disease of old 

 age, and must take its course. 



A terrier uttered a continual loud stertorous sound in breathing, which 

 could be plainly heard in our parlour when the dog was in the hospital. 

 The animal was evidently much oppressed and in considerable pain. He 

 made continual, and generally ineffectual, efforts to sneeze. When he did 

 succeed, a very small quantity of pus-like fluid was discharged ; the dog 

 was then considerably relieved, but a quarter of an hour afterwards he 

 was as bad as ever. I ordered a slight emetic every third day. There 

 was some relief for seven or eight hours, and then he was as bad as ever. 

 I could neither feel nor see any cause of obstruction. The owner became 

 tired, and the dog was taken away ; but we could not learn what became 

 of it. 



Another terrier was occasionally brought for consultation. The dog 

 breathed with considerable difficulty, and occasionally snorted with the 

 greatest violence, and bloody purulent matter was discharged ; after which 

 he was somewhat relieved ; but, in the course of a few days, the obstruction 

 was as great as ever. I am not aware of a single instance of this affection 

 of the pug being completely removed. The discharge from the nostrils 

 of the bull-dog is often considerable, and, once being thoroughly established, 

 is almost as obstinate as in the pug. 



'THE SENSE OF SMELL. 



In the dog we trace the triumph of olfactory power. How indistinct 

 must be that scent which is communicated to, and lingers on, the ground 

 by the momentary contact of the foot of the hare, the fox, or the deer ; 

 yet the hound, of various breeds, recognises it for hours, and some sports- 

 men have said for more than a day. He also can not only distinguish 

 the scent of one species of animal from another, but that of different 

 animals of the same species. The fox-hound, well broken-in, will rarely 

 challenge at the scent of the hare, nor will he be imposed upon when the 

 crafty animal that he pursues has taken refuge in the earth, and thrusts 

 out a new victim before the pack. 



The sense of smelling is, to a certain degree, acute in all dogs. It is 



