100 THE DISEASES OF THE DOO. 



are a little larger and the corner ones almost tush-like, 

 especially in the upper jaw. The four tushes are long, 

 recurved, have large fangs, and so are formidable weapons 

 of offence and defence, and useful for prehensile purposes. 

 Of the molars, those anteriorly placed are rudimentary; 

 especially the small premolars which are immediately 

 behind the lower tushes. The fourth tooth in the upper 

 jaw on each side and the fifth in the lower are the largest 

 teeth, and they lose somewhat the sharp edge of the true 

 canine molar and become widened. The teeth behind 

 them are small and best adapted for crashing ; but the 

 back teeth are lost in the short-nosed breeds of dogs as 

 the palate shortens with age, their fangs become exposed 

 and carious, and the teeth actually drop out as functionally 

 superfluous and structurally expelled for want of space. 

 These molar teeth are not such ponderous, massive, com- 

 plex organs as we see in herbivora, they are simple in 

 structure, have but little crusta petrosa, and their fangs 

 are numerous and small. We might think this simplicity 

 of structure would secure them from such diseases as are 

 seen in the horse, and undoubtedly it does so. The 

 diseases of the teeth of the dog differ to a remarkable 

 degree from those of herbivora. In the latter we find 

 disorder due to overgrowth with non-apposition, in the 

 former we find accumulations of tartar, loss of teeth, and 

 caries, especially of the fangs. 



Tartar Accumulations of a blackish colour are very 

 frequently found on the teeth. They are greatest around 

 the neck of the tooth and thus interfere with its proper 

 fixture in its socket, cause ulceration of the gum, and 

 absorption of the margin of the alveolar cavity. In these 

 cases the mouth is very offensive to the smell, there is a 

 certain amount of ptyalism, the lips may be ulcerated, and 

 the teeth are loose. In some cases the teeth are even 

 displaced by the amount of matter deposited. These 

 unpleasancies are not often seen in healthy, hard-fed dogs, 

 but prove very troublesome to pets, and a source of great 

 disgust to their owners. They are caused by a vitiated 

 state of the secretions of the mouth the result of indiges- 



