In heavy milkers, before and just after calving, it is the rule that the mammary gland is enlarged, hot, tense, and tender, and that a slight exudation or pasty swelling extends forward from the gland on the lower surface of the abdomen. This physiological congestion is looked upon as a matter of course, and disappears in two or three days when the secretion of milk has been fully established. This breaking up of the bag may be greatly hastened by the sucking of a hungry calf and the kneading it gives the udder with its nose, by stripping the glands clean thrice daily, and by active rubbing at each milking with the palm of the hand, with or without lard or, better, with camphorated ointment. The congestion may be at times aggravated by standing in a draft of cold air or by neglect to milk for an entire day or more (overstocking, hefting) with the view of making a great show of udder for purposes of sale. In such cases the surface of the bag pits on pressure, and the milk has a reddish tinge or even streaks of blood, or it is partially or fully clotted and is drawn with difficulty, mixed, it may be, with a yellowish serum (whey) which has separated from the casein. This should be treated like the above, though it may sometimes demand fomentations with warm water to ward off inflammation, and it may be a week before the natural condition of the gland is restored. INFLAMMATION OF THE UDDER (SIMPLE MAMMITIS). Congestion may merge into active inflammation, or it may arise direct, in connection with exposure to cold or wet, with standing in a cold draft, with blows on the udder with clubs, stones, horns, or feet, with injury from a sharp or cold stone, or the projecting edge of a board or end of a nail in the floor, with sudden and extreme changes of weather, with overfeeding on rich albuminous feed like cotton seed, beans, or peas, with indigestions, with sores on the teats, or with insufficient stripping of the udder in milking. In the period of full milk the organ is so susceptible that any serious disturbance of the general health is liable to fall upon the udder. _Symptoms._--The symptoms and mode of onset vary in different cases. When following exposure there is usually a violent shivering fit, with cold horns, ears, tail, and limbs, and general erection of the hair. This is succeeded by a flush of heat (reaction) in which the horns, ears, and limbs become unnaturally warm and the gland swells up and becomes firm and solid in one, two, three, or all four quarters. There is hot dry muzzle, elevated temperature, full, accelerated pulse, and excited breathing, impaired or suspended appetite and rumination, with more or less costiveness, suppression of urine, and a lessened yield of milk, which may be entirely suppressed in the affected quarter.