_Abundant_ but not excessive _exercise_ is more necessary than anything else to the preservation of the health of the hoof. It aids the circulation of blood within the foot, and, therefore, the growth of the horn. Horses which perform hard, regular work have, as a rule, better hoofs than those which stand the greater part of the time in the stable. Poulticing hoofs with clay, bran, linseed-meal, or white-rock, or standing them in water is unnecessary if they have had proper care, but will sometimes be of benefit when the hoofs have been neglected, and especially so for front hoofs. The latter are more exposed to drying influences, and the shoes prevent the moistening process by keeping the hoofs partially or completely removed from contact with the earth. _Oiling alone is not sufficient to soften horn_, but must always be preceded by permeation of the horn with water. =Oiling without first cleansing the hoof is useless, because this soon produces a greasy crust underneath which the horn is crisp and brittle.= The surest sign of cleanliness of a hoof is the appearance of the natural color of the horn, the latter appearing translucent even after the hoof-ointment has been applied; therefore, blackened hoof-ointments should not be used. When hoofs are exposed to too much moisture (muddy roads, melting snow, etc.) an addition of wax or common yellow rosin to the hoof-ointment is recommended to prevent too great softening of the horn. _No hoof-ointment has any direct influence upon the growth of the horn._ Inasmuch as it is a fact that the very best shoeing injures the hoof, it is advisable to allow horses to go barefoot whenever it is possible. This applies especially to horses that from any cause are thrown out of service, presupposing, of course, that the nature of the hoofs will allow them to go barefoot. PART III. CHAPTER VII. GENERAL REMARKS CONCERNING THE SHOEING OF DEFECTIVE HOOFS AND LAME HORSES. The boundary between health and disease of the hoof is difficult to determine, especially when we have to deal with minor defects of structure or shape of the hoof. Ordinarily, we first consider a hoof diseased when it causes lameness. However, we know that diseases of the hoof may exist without lameness. Therefore, a hoof should be regarded as diseased or defective when the nature of the horn, the form of the hoof, or the parts enclosed by it, deviate from what we consider as normal or healthy (see page 81), whether the service of the animal is influenced by it or not. Front hoofs become diseased or defective more readily than hind hoofs, because they bear greater weight, have more slanting walls, and are more exposed to drying influences. =All normally wry hoofs and acute-angled hoofs become more readily diseased than regular and upright (stumpy) hoofs.=