Horses at the middle period of life are more valuable than when very young or very old. It is not remarkable, therefore, that certain devices are adopted for the purpose of, in the first place, facilitating the cutting of the permanent teeth to make young horses look older than they are, and, on the other hand, to restore the " mark " when it is obliterated, for the purpose of making old horses look younger.

The extraction of the temporary teeth will undoubtedly assist the development of the permanent organs beneath them, and if the operation is properly done the deception would not be detected; but as a professional operator would not be likely to be consulted in the matter, it is usually badly done, and defeats its object, either by destroying the germ of the new tooth below and leaving an obvious gap in the mouth, or by causing it to be displaced, and in that way leading to a derangement of the dental line. The second form of deception, termed "bishoping", is probably rarely or never practised now. It consists in carving a properly-shaped cavity in the extremely hard bone of an old tooth and making it black by heat, a performance which would require great mechanical skill and most perfect apparatus, and, however well performed, certainly would not deceive anyone who had the slightest claim to be an anatomist or a judge of a horse.