A more serious form of the disease is known as contagious mammitis, and is due to invasion of the gland by bacteria. In cases of this kind the inflammation is more extensive and the disorder calls for more careful treatment. Since the milk contains bad bacteria, it is necessary to destroy them so as to prevent spreading of the disease. The milker should have clean hands and should wash them in a disinfecting solution before milking another cow. The milk tube may be necessary in withdrawing the milk. After the milk has been removed from the udder, inject a solution of peroxide of hydrogen or dioxygen or a solution of carbolic acid, 1 part to 50 parts of boiled water. After the solution has acted for a few minutes, it should be milked out. The external treatment for contagious mammitis should be similar to that of ordinary mammitis. =MANGE.=--See Scab in Cattle. =MILK FEVER.=--It is a remarkable fact that this disease occurs most commonly in cows which calved easily. This is explained by the fact that in such cases the os uteri remains relaxed for a greater length of time than it does in cases of difficult parturition. Milk fever generally occurs in cows which are heavy milkers, and great eaters. Keeping the animals in permanent stables, and feeding large quantities of rich food while they are giving no milk are predisposing causes. The disease makes its appearance usually in from 24 to 48 hours after parturition. It seldom occurs after the third day, and some authors state that it has never been recognized before the starting of the milk secretion. The most salient symptoms to the average layman would, perhaps, be the anxious expression of the animal, bellowing and mounting into the manger. Later they become very weak, stagger and fall, and are unable to rise. The members are usually extended in a rigid position. A rattling or whistling noise is heard in case the larynx is paralyzed. The feet, ears and horns feel cold to the touch. When a case is going to recover we see improvement as early as the second or third day. Recovery is usually complete at the end of from two to five days. Milk fever is one of the cases where the old maxim, an ounce of prevention is worth a pound of cure, is doubly applicable. If proper precautions were taken a large number of cases could be prevented. Give the pregnant animals daily exercise, and decrease their allowance of food.