thin_; this must give us a bearing upon the frog and the sound part of the foot. We use the lightest shoe, truly fitted with the rasp, not burned on. The horse should then be worked regularly, and he will experience at once the benefit of a return to "first principles" and natural action. [Illustration: FOOT, WITH SHELL REMOVED.] CHAPTER V. SIMPLE CASES OF CONTRACTION. Contraction, in a greater or less degree, is exhibited by all horses, of every grade, that have been shod in the common way, except in those more unfortunate cases that have resulted in a breaking of the arch of the foot, from lack of the natural frog support, when the phenomena of "dropped sole" are found, and the usual accompaniment of "pumiced feet." It may seem superfluous to say that the power and action of the horse are greatly restricted by contraction. The cartilaginous fibre that forms the bulk of the substance of the foot behind the great back sinew is squeezed into narrow space, the working of the joints compressed, and inflammation at the joints, or at the wings of the coffin-bone, is excited; in worse cases navicular disease is established, or, from inadequate circulation, thrush holds possession at the frog, or scratches torment the heels. When simple contraction--shown in the narrow heel, dried and shrunken frog, and "pegging" motion of the horse--is the case, our design is at once to restore the natural action of the foot. This must be done by expansion, and that is to be had from frog-pressure, according to the directions in the preceding chapters. If navicular disease has commenced, and the animal is decidedly lame, we have a difficult case. The membrane of this important bone, in some cases of contraction, becomes ulcerated, and the bone itself may be decayed, or adhesion between the coffin-bone and the navicular and pastern may take place. Without expansion there is no possibility of relief; local bleeding, poulticing, and all the drastic drugs of the veterinary will be invoked in vain. QUARTER AND TOE CRACK. [Illustration: QUARTER CRACK--FULL SHOE.] This disease, usually attributed to "heat," "dry weather," "weak feet," etc., is one of the common symptoms of contraction, and can be entirely cured with the greatest ease; nor will it ever recur if the hoof is kept in proper condition.