To the members of my profession, I am deeply indebted. When they knew the subject on which I was engaged, each volunteered to aid me, and generously gave me the benefit of that experience, which personally I was unfortunate in not possessing. It was acknowledged, that upon the teeth, some work which might be depended upon, was sadly needed, and to render the present worthy of the confidence of the public, all to whom I applied cheerfully gave their utmost help. From their cordial communications and disinterested co-operation, I learnt much, and gained many valuable ideas. _16, Spring Street,_ _Westbourne Terrace._ THE HORSE'S MOUTH, SHOWING THE AGE BY THE TEETH. 1. _That the teeth of the horse denoted the age of the animal_ appears to have been a very ancient belief, which the experience of centuries seems in no degree to have weakened. As a general rule, applied within certain limitations, the impression is certainly well founded; for perhaps no development is more regular than the teeth of the horse, and no natural process so little exposed to the distortions of artifice. We are, nevertheless, not to expect that the animal carries about in its mouth a certificate of birth, written in characters so deep or legible that they cannot be obliterated or misinterpreted. The indications to be discovered by an inspection of the mouth of the horse, however, are so generally true, that in these dependence may be placed; although they are not so arbitrary or invariable, that upon them in every instance an absolute opinion can hastily be pronounced. He who would judge of the age by the teeth, must therefore be content to study and prepared to encounter difficulties. In proportion as he has done the one, and is fortified thereby to overcome the other, will be his success. There is no secret charm which will enable man to unravel Nature's mysteries. Her ways are regular, but they are not uniform--her laws are fixed, but her acts cannot be measured by a system of rule or compass. The qualified judge alone will read the teeth correctly; but in proportion as the task is difficult, will be the candour and caution of him who fulfils it properly. He will make allowance where certain marks are indistinct or absent--he will not feel himself degraded by a confession of inability to speak with certainty when the signs are complex or confused--and above all, he will be cautious before he pronounces a final opinion, and gives it forth as a decision, against which there ought to be no appeal. The Veterinary Practitioner knows from repeated trials, tested by long experience, that the teeth of the horse are worthy of attention; he feels that their indications, scientifically interpreted, will seldom mislead; but he does not regard them with a reverence resembling that originating from an antiquated superstition, or look upon them as the exemplifications of a principle which admits of no exceptions.