Causes. In sheep the use of baths containing corrosive sublimate, or of mercurial ointment for acariasis or other cutaneous parasitism. In other animals it comes mostly from licking mercurial dressings applied to the skin—calomel, red precipitate, mercurial ointment, protoiodide of mercury. The red iodide being more irritating is less frequently taken in. The modern extensive usage of mercuric chloride solutions as surgical antiseptics opens up a new channel of infection. In the injection of the uterus or of large abscesses, or in the daily irrigation of large wounds a dangerous amount may be absorbed. The application of this agent as a caustic in cases of tumors is correspondingly dangerous. Vapors from metallic mercury in confined spaces as in ships’ holds, or from fires on which the mercurial compounds have been thrown, are ready means of poisoning, acting primarily on the air passages and lungs and later on the mouth. The condensation of mercury on vegetation and other food products in the vicinity of factories where mercury is handled (Idria) affects domestic animals directly. Finally the small animals are poisoned by eating the mercurial rat poisons, and all animals are subject to malicious mercurial poisoning, with sublimate especially.
Stomatitis with fatal pharyngitis and enteritis will result in the horse from 2 drs. of corrosive sublimate. About one-half of this may poison the ox, and one-fourth the sheep or goat. Ruminants are more susceptible to the toxic action of mercury than monogastric animals, one evident reason being the long delay of the successive doses in the first three stomachs, so that finally a large quantity passes over at once into the fourth stomach and duodenum for absorption. The old too are more readily poisoned than the young, as the functions of the kidneys are more impaired in age and the poison is not eliminated with the same rapidity.
Symptoms. Mercurial stomatitis is a local manifestation of a general poisoning. Salivation is one of the most prominent phenomena, the watery saliva falling in streams from the angles of the mouth. The buccal mucosa generally becomes red and swollen and the tongue becomes indented at the edges by pressure against the molars. The gums especially suffer and the teeth raised in their sockets by the swelling of the periodontal membrane, become loose, and easily detached. The mucosa of the gums becomes soft and spongy, bleeds readily under pressure and soon shows erosions and ulcers. This condition extends to the lips, cheeks and lower surface of the tongue while the upper surface of the latter organ, the fauces and pharynx commonly escape. The breath and buccal exhalations are very offensive, and the animal loathes food, and has little power of mastication or deglutition. Sometimes the ulcers extend even to the bones.
Along with these local symptoms there are usually gastro-intestinal irritation, tympany, inappetence, continuous rumbling in the belly; badly digested fœtid stools, often diarrhœa, small weak pulse, hyperthermia, accelerated breathing, cough, and great langor and prostration. A tendency to blood extravasation is shown in sanguineous fæces, epistaxis, bleeding from the mouth, the throat or the womb and even into the skin. Pregnant females may abort. The eyes are dull and sunken, and the conjunctiva yellow. Eczematous or pustular eruptions may appear on the skin on the nose, lips, neck, back, loins, croup or perineum.
Lesions. In addition to the lesions described above, there are usually gastro-intestinal inflammation, œdema of the peritoneum and pleura, in the lung as well as in the serosæ, (pneumonia is not uncommon especially in sheep), intestines, kidneys and muscles, hæmorrhagic spots are not uncommon, the blood forms a loose black coagulum, and the encephalon is anæmic and softened.
Treatment. The first consideration is to cut off the supply of mercury. Mercurial applications on the skin should be washed off with tepid water and if necessary soap. An application of sulphide of potassium will precipitate the mercury in an insoluble form. For mercurial agents in the alimentary canal an emetic may be given (if the animal is one susceptible to emesis) followed by a saline laxative. This may be combined with or followed by raw eggs, mucilage, wheat gluten or other albuminoid, sulphide of potash or sulphur, to precipitate the mercury and prevent its absorption. Later, when the bowels have been cleared, iodide of potassium in small doses will serve to dissolve and remove what mercury may be lodged in the tissues.
Locally one of the best applications is chlorate of potash as a mouth wash, 2 drs. to the quart of water. To this may be added tannic acid or other vegetable astringent and even alcohol.
Finally a course of iron and bitter tonics will serve a good purpose in restoring the general tone.
STOMATITIS FROM CAUSTICS.
Caustic Alkalies; symptoms, lesions and antidotes. Caustic Acids; symptoms, lesions and antidotes. Caustic salts; symptoms, lesions and antidotes.