In other cases the shivering escapes notice, the general disorder of the system is little marked or comes on late, and the first observed sign of illness is the firm swelling, heat, and tenderness of the bag. As the inflammation increases and extends, the hot, tender udder causes the animal to straddle with its hind limbs, and, when walking, to halt on the limb on that side. If the cow lies down it is on the unaffected side. With the increase in intensity and the extension of the inflammation the general fever manifests itself more prominently. In some instances the connective tissue beneath the skin and between the lobules of the gland is affected, then the swelling is uniformly rounded and of nearly the same consistency, pitting everywhere on pressure. In other cases it primarily attacks the secreting tissue of the gland, then the swelling is more localized and appears as hard, nodular masses in the interior of the gland. This last is the usual form of inflammation occurring from infection entering by the teats. In all cases, but especially in the last-named form, the milk is suppressed and replaced by a watery fluid colored with blood (sometimes deeply) and mingled with masses of clotted casein. Later it becomes white and purulent, and in many cases of an offensive odor. The course of the disease is sometimes so rapid and at others so slow that no definite rule can be laid down. In two or three days, or from that to the end of the week, the bag may soften, lose its heat and tenderness, and subside into the healthy condition, even resuming the secretion of milk. The longer the inflammatory hardness continues the greater the probability that its complete restoration will not be effected. When a portion of the gland fails to be restored in this way, and has its secretion arrested, it usually shrinks to a smaller size. More commonly a greater quantity of the inflammatory product remains in the gland and develops into a solid, fibrous mass, causing permanent hardening (induration). In other cases, in place of the product of inflammation developing into a fibrous mass, it softens and breaks down into white, creamy, liquid pus (abscess). This abscess may make its way to the surface and escape externally, or it may burst into a milk duct and discharge through the teat. It may break into both and establish a channel for the escape of milk (fistula). In the worst types of the disease gangrene may ensue, a quarter or half or even the whole udder, losing its vitality, and sloughing off if the cow can bear up against the depressing influence. These gangrenous cases are probably always the result of infection and sometimes run a very rapidly fatal course. I remember one to which I was called as soon as the owner noticed it, yet I found one-quarter dark blue, cold, and showing a tendency to the formation of blebs containing a bloody secretion. The cow, which had waded through a depth of semiliquid manure to reach her stall, died within 24 hours.