A HOUSE’S FACE

Southland Times, Issue 19461, 28 January 1925, Page 8

A HOUSE’S FACE

WHY IT HAS GROWN LONG. Why are the eyes of a horse placed so far upward from its mouth and why does the animal have such long cheek-bones? Nature has a reason for everything, declares the New York Times. The grassy plains were just beginning to make their appearance on the surface of the earth. All the land had been under water, and when it flowed off and let the vegetation grow on the fertile soil all the first green things were seft and juicy. But as the land became less and less damp the soft green things gave way to the tall grasses of the prairies. Grass is actually hard. This is because the grass, when taking up its mineral food from the soil, adds silica to its blades. , The ancestors of the modern horse—much smaller than the magnificent animals of to-day—were used to eating the soft, juicy plants. Their teeth were soft and remained soft on that account, having almost no enamel. When these little horses were forced to eat the hard grasses the silica ground against their teeth and wore them down rapidly. The change from the soft plants to the hard grasses was, of course, very gradual. This gave Nature an opportunity to bring about, through very slow processes, a new arangement of teeth to meet the new r condition. Enamel began to form on the horses’ teeth, but this wore off.

Look a horse in the mouth and note the arrangement of the enamel. Instead of being on the outside of the teeth, as in human beings., it is arranged in wavy lines running over the crowns, and these fines are deeply imbedded in the bulk of the tooth. This enamel grows with the teeth as a grinding edge for chewing the sharp grasses.

Teeth form slowly, so that it became necessary for the horse’s teeth to be much longer than the average. The teeth grow slowly out from the jaws all through the life of the horse, slowly forming on the lower end as they are worn away on the grinding end. But long teeth take up more room than short teeth, so Nature had, somehow, to make room for them. In a short face, which the first horses had, the teeth in the upper jaw would interfere with the eyes. So, through little-by-little movement's extending over thousands of years, Nature moved the eyes back to where they are to-day, to make plenty of room for the horse’s new teeth.