Acts prominently upon the organs of animal life, upon the mucous membranes, the lymphatic glands, the skin, the muscular tissues, and the tissues which compose the joints. The primary condition produced is one of irritation, and this may proceed to inflammation, or, if it stops short of that, produce serous discharges, in the form of evacuations or oedema. This condition of irritation affects most prominently the skin. " Even contact of the leaves of the plant, or proximity to them, produces an eruption, varying in intensity, from the slightest erythema to the gravest form of vesicular erysipelas." The action of Rhus upon mucous membranes resembles that which it has upon the external skin, simulating eczematous and vesicular eruptions ; it acts most powerfully upon the conjunctiva, though affecting other mucous surfaces to a greater or less degree. In the sero-fibrous tissues the characteristic primary irritation develops a rheumatoid inflammation of the joints and muscles, affecting particularly the fascia, tendons, sheaths of nerves, ligaments, and fibrous tissue. The lymphatic glands throughout the body become enlarged and inflamed. The cellular tissues become infiltrated with a serous exudation, and the functions of nutrition are depressed and impaired. On the organs of animal life Rhus acts secondarily, producing dullness of the senses, and a condition of the cerebral system closely resembling that present in low grades of typhus fever. The chief characteristic of Rhus is the prominent aggravation of its symptoms during repose, and amelioration by motion. Characteristic symptoms.