=HORN FLY.=--A small insect about half as large as the common house flies, and very much like them in appearance. Horn flies swarm about the head and settle near the base of the horn, where they bite and cause much irritation. They also attack cattle on the back and sides and flank. The fly mixtures that are commonly advertised, and applied by means of a hand-spray, are excellent for keeping the pests away. A good home mixture to apply at the base of the horns is made of pine tar, kerosene, and fish oil. Use this in equal parts, and apply with a brush. =HOVEN.=--See Bloating in Cattle. =HYDROCEPHALUS.=--See Water in the Brain. =HYDROPHOBIA=, also called rabies and mad dog, is an infectious disease caused by some invisible organism. The disease is transmitted from one animal to another by the bite of an animal which is suffering with the disease or by direct inoculation. It is more common in the dog than any other animal, from the fact that dogs run at large and have a tendency to bite other dogs with which they come in contact while they are suffering with the disease. The dog shows two forms, furious and dumb. In the furious form the animal at first seeks dark places, but is usually restless and will move from one place to another. This condition lasts for a day or two, after which time he becomes more restless and may go 30 miles in a day. He will drink water, eat sticks, stones, and bite other dogs, horses, and cattle, less often man. This condition will last from one to four days, and then the dog becomes partly paralyzed, so that he can no longer swallow, or his legs may be affected, so that he will lie in one place, and usually dies after a few days longer. In the dumb form, the animal seeks dark places, is rather restless, the throat and lower jaw become paralyzed, he is unable to swallow or to close his mouth and, therefore, cannot bite. Sometimes they will change from one form of symptoms to the other. In the horse the symptoms vary somewhat from those in the dog. The horse is restless, usually violent and will kick and bite, oftentimes showing sexual excitement. He may break his teeth on the manger and oftentimes bites his own flesh at the place where he has been bitten by the dog. The symptoms usually develop in from eight to twenty-eight days after the animal is bitten, but may not develop for six months. The disease runs its course in from two to ten days, with a fatal termination. There is no treatment for the disease after the symptoms have developed. In case man is bitten he should take the “Pasteur” treatment, which is a preventive, and it should be taken in a very short time after being bitten. After the symptoms begin to show it is too late to take treatment. =HYDROTHORAX.=--See Water in the Chest.