=Calculus= or stone may be present, either in the stomach or in the canal. Those in the stomach are of small size; those within the intestines may attain the weight of more than twenty pounds. Those of the stomach are always smooth, as also may be those of the bowels. To the intestines, however, there are common three kinds of, or differently composed calculi: the triple phosphate or the earthy; one formed of the minute hairs which originally surrounded the kernel of the oat; and another composed of dung, held together by the mucous secretion of the bowel. Any of these calculi may, as the size increases, gradually stretch the intestine; thus forming a living sac within which the stone abides. While it remains there, the food passes over it and no injury is occasioned. But by any movement it is likely to be dislodged and thrown into the healthy channel: There it is firmly grasped with such force as to produce rupture of the intestine, and the hold is only relaxed after inflammation has ended in mortification and in death. The bowels, in truth, are impacted by calculus. The passage is stopped. However different the causes of abdominal injury may appear, they are each generally characterized by the severest possible abdominal pain. This symptom is often so violent that the agony conceals all other indications; or if any others can be exhibited, they are so partially shown and displayed for so very brief a space as not to permit of their being rightly interpreted. It is very desirable that every one should witness a powerful horse in its agony. No stronger means could be found for enforcing such a lesson than the sufferings which spring from abdominal injuries. When this is proposed it is not intended the person should look on misery only so long as the spectacle stimulated his feelings; but that he should watch hour after hour and behold the afflicted life resigned under the pressure of mighty torment. Were such a sight once contemplated--were man fully conscious of how brimming with horrible expression every feature of the horse's frame can become--the thought of anguish wrenching life out of so huge a trunk would surely compel the better treatment of a gentle, inoffensive, and serviceable slave. Ruptured stomach a little forethought would prevent. The triple phosphate calculus is common among millers' horses, which are foully fed from the sweepings of the shop. But if man will oblige duty to bow before convenience, or make it secondary to expense, the misery he inflicts will surely in justice recoil upon himself.