Symptoms of _nervous disorder_ are too numerous to be here traced to local lesions. Motor paralysis of one limb may, however, suggest injury to its motor nerves, to the same side of the spinal cord, or of the opposite half of the cerebrum. Paraplegia almost always indicates injury to the cord. Sensory paralysis of one side may depend on disease of the opposite corpus striatum. The animal moves in a circle when a tumor (coenurus in sheep) exists in the roof of the lateral ventricle presumably pressing on the ganglia on its floor. An animal rolls on its axis when there is a lesion of the median cerebral peduncles, of the supero-external portion of these peduncles, of the posterior part of the encephalon, or of different parts of the hemisphere. Amaurosis suggests disease of the corpora quadrigeminia. Loss of coördination of muscular movement usually implies some lesion of the cerebellum. Vertigo may imply disease of the encephalon (congestion, anæmia, inflammation, dropsy, hæmorrhage, tumor, abscess); it may be disease of the internal ear; it may be digestive disorder connected often with cryptogamic poisoning; it may be heart disease with obstruction of the jugular veins; it may be parasites in the nasal sinuses; or it may be disease of the eye. Coma occurs in most congestions and pressures on the encephalon, and like vertigo in poisoning by alcohol, solanine, monoxide of carbon, etc. In acting on any ganglionic centre the agent may, according to its degree, operate positively or negatively, producing spasms, or paralysis as the case may be. As in the case of other visceral affections the specific diseases must be referred to for particular symptoms. For the more precise points in diagnosis, including chemical, physical, electrical and instrumental methods, etc., the reader is referred to the special diseases. PROGNOSIS. Definition. Demands on the veterinarian, the question of economy. Basis of Prognosis. Cause of the illness, internal or external, vital or nonvital organ, enzootic, fatigue, infection, in one or two symmetrical vital organs, regular or irregular in its course, persistence, relapse, complications, effect of treatment, appetite, temperature, pulse, breathing, youth, age, debility, previous disease, breeding, climate, season.