As time progresses, however, all the white disappears, and its place is filled by a material not unlike lamp-black when thoroughly incorporated with water. These growths increase both in number and in size. Should one be cut into after it is fully matured, an inky fluid follows the knife. The disease is not confined simply to external tumors; the coverings to nerves, the coats of arteries, and the recesses of the closest bones, are each found to bear minute evidences of a melanotic tendency. The deposit, however, seems principally to attack the internal organs. The interior of the sheath is not unfrequently clogged to that degree which forbids the passage of the natural emission; while the preceding engraving of a loaded spleen by no means represents an extreme case. A tumor should be admirably placed for operation, and its removal should be almost imperative, before the surgeon presumes to meddle with it. As a general rule, the best treatment for =melanosis= is to let it alone. Our present knowledge points to no medicine which can prevent or disperse such deposits, and the tumors appear to resent the slightest interference. The integrity of one swelling being violated seems to start off the disease with enraged intensity. If let alone, melanosis may exist for years, and cause little inconvenience to the body in which it resides. The horse is, by its daily service, exposed to various accidents. The large majority of the tribe perish before their youth has passed. The animal may, therefore, cease to live by other causes than disease, or die before disease has become formidable. But irritate the system by employment of the knife, and a lamentable malady may speedily render the knacker's office an act of charity. Above all, let the master not permit any man to blister, seton, rowel, fire, stimulate, or slough out the tumor; such deeds are cruel folly. Bleeding is worse than useless. Purging weakens the body which disease is sapping. All medicines used in ignorance are probable hazards. Let such things, therefore, be discarded; but if something must be done, let the animal have daily an eight-ounce dose of any bland vegetable oil. Some linseed may likewise be mingled with the corn, or a decoction of the whole linseed may be presented as drink before the seeds themselves are given with the oats. [Illustration: THE COLORED HORSES WHICH ALONE ARE EXPOSED TO MELANOSIS. TO THE LEFT IS THE OLD HORSE, WHICH HAS BEEN GRAY; TO THE RIGHT IS THE YOUNG ANIMAL, WHICH WILL WITH AGE BECOME WHITE.]