The horse's mouth, showing the age by the teeth — Inside the Classic

A Mouth of Named Horses

Mayhew repeatedly cites particular horses as evidence for his claims. The description of the five-year-old mouth was 'amply proved' by comparing it with horses of various breeds, including blood horses, and 'last tested by the aspect presented by the teeth of the well-known horse, The Baron.' Earlier, the drawing of the four-year-old mouth was 'corroborated and corrected' by the mouth of Crowley's hunter. These references are not ornamental; they function as a chain of empirical verification. The reader is asked to trust not only the author's expertise but the specific animals he has examined. This practice sets Mayhew's work apart from generic veterinary manuals, offering a traceable, specimen-based authority.

The Corner Tooth as Chief Witness

Mayhew assigns special importance to the corner incisor, which he calls 'the shell tooth' because its infundibulum (the central cup) is 'better exhibited and longer retained than in the other incisors.' After the fourth year, he states, 'the corner nipper leads, in a great measure, if it does not entirely sway, the judgment.' This focus on a single tooth as the primary age indicator is a distinctive structural choice. The text repeatedly returns to the corner tooth's wear, its posterior margins, and its closing with the opposite tooth. For the reader, this emphasis provides a clear observational target: when examining a horse's mouth, the corner incisor is the key to accurate aging.

Reading the Tables and the Infundibulum

Mayhew's method relies on reading the 'tables'—the chewing surfaces of the incisors. At five years, the tables are not yet formed; only the anterior edges are level. The infundibulum, a dark cavity, is a critical marker. Mayhew notes that in some cases, when the crusta petrosa lining is thick, 'no infundibula may be distinguishable,' yet the cavity's form can still be traced by 'a line of enamel.' He also describes the changing color of the crusta petrosa, which can give a six-year-old mouth a darker aspect than a younger one. These details demand careful visual inspection, and Mayhew's prose mirrors that precision, guiding the reader to look for subtle differences in enamel transparency and wear patterns.

The Practical Purpose of Age Determination

Mayhew does not present age determination as a purely academic exercise. He states that animals are 'esteemed suitable for particular uses, only after the fifth year has been completed,' and that all horses are 'less liable to disease when the mouth has been perfected.' The distinction between a four-year-old and a five-year-old mouth is therefore 'of some moment.' This practical framing gives the detailed dental descriptions a clear purpose: to help the reader make informed decisions about a horse's fitness for work or purchase. The manual is thus a tool for the horse owner or buyer, not merely a zoological curiosity.

Mayhew's manual rewards a slow, comparative reading. The engravings and wood-cuts are essential companions to the text; the descriptions of wear patterns, infundibula, and crusta petrosa are best understood with the images in view. Readers new to the subject may find it helpful to start with the sections on the five-year-old mouth, where the system is most fully laid out, before moving to the earlier ages. The repeated references to named horses also invite the reader to consider the manual as a record of actual examinations, not just a theoretical system.

I found myself turning the pages of that old equine dental manual, tracing the engraved teeth, and I thought of another patient craft—the quiet arithmetic of bees, their own cycles of growth and wear. Both are measured in patient lines, an old The honey bee: a manual of instruction in apiculture — Story, Setting & Ideas, where a similar gentle attention to form lingers, a comfort in the fixed order of things.