The leeches which suck the blood of the horse may be divided into two classes, the external parasites which attach themselves to the skin of the legs and adjacent parts of the horse, and the Haemopis Sanguisuga, and others of this class, which, not being able to penetrate the skin, endeavor to enter the mouth or nostrils of the horse when he is drinking or grazing in wet and leech-infected pastures. They sometimes cling to the mucous membrane of the eyes. The horse leech, which lives in the water, usually gains access to the mouth and nostrils of the animal, when young and not more than one-tenth of an inch long. They rarely go beyond the air and food passages, generally fastening themselves to the walls of the windpipe and gullet, where they cling till the animal dies from loss of blood or suffocation. They often cause bleeding from the mouth and nostrils, and may be seen by close examination. TREATMENT.—Endeavor to build up the condition of the animal with suitable food. Also feed liberal quantities of rock salt. Where the leeches cling tightly to the mucous membranes of the mouth and nostrils, it is well to cause the horse to inhale the vapor from hot water containing turpentine. LOCK-JAW. (_Tetanus_) CAUSE.—The bacilli of Tetanus are widely distributed and can be found in practically every part of the globe. Their favorite place of production, however, is in barn yards and marshy ground. They are frequently swallowed by stock along with forage, and can often be found in recently expelled feces. The most favorable temperature for their development is about 70° F. They act by means of extremely virulent poisons which they produce, and which causes the terrible symptoms that are characteristic of the disease. SYMPTOMS.—The muscles of expression are usually the first brought under the continual spasm of tetanus, and when thus affected give the face of the animal a pinched and drawn-in appearance. The other muscles of the head and those of the neck are next attacked. The mouth is closed, the nose poked out, the head elevated. The muscles of breathing, and those of the limbs, become contracted so that the neck is hollowed, and the tail is raised, the horse stands with outstretched limbs. The animal shows great stiffness or rigidity in attempted movements. The eyes are sunken, and when startled or excited, the breathing is quickened and the flanks have a wrinkled or corrugated appearance. Death may quickly occur from continuous spasms of the muscles of the throat. Another sign is the flying up of the accessory eyelid when the animal is excited.