(2) Great exudation of fluid composed of lymph, fibrin, and broken-down cells in the lymph spaces of the mucous layer, forming blisters. (3) Intense swelling and congestion of the papillary layer. (4) Swelling of the connective tissue and elastic fibres in the true skin. (5) Thrombosis in some superficial blood vessels. (6) Leucocytes poured out around the blood vessels. +Clinical Stages.+ (1) Stage of blistering, edema, dermatitis, toxemia, pain, chill and shock. (2) Discharge or absorption of contents of the blister with shedding of dead layers of epidermis. (3) Reproduction of cells of the mucous layer from those of the germinal layer, which have formed the floor of the blister. +BURNS OF THE THIRD DEGREE+ +Pathology.+ Charring of the whole skin through the reticular layer, or deeper. It may involve only skin, or include any underlying structures, fascia, muscles, blood vessels or bone. The essential feature is the total death of hair follicles, oil and sweat glands, with consequent destruction of all germinal epithelium. +Clinical Stages.+ (1) Stage of destruction of tissue with underlying inflammation. If extensive, this degree of burn causes shock, probably non-toxic. During the early stage there is apt to be great pain from injury to the nerves in the sick layer, but not so great as in that of second degree burns where the number of injured nerves is greater. (2) The general effects (toxemia, blood changes, embolism, congestion of vital organs with resultant chill and shock) are probably little different from those in extensive burns of the second degree, as few burns are purely third degree burns, but if extensive they have also large areas of second degree burns. (3) Stage of sloughing. During this stage the second degree portion of the burn passes through its various stages and heals. The dead tissue shows at its edges a line of cleavage from the surrounding living skin. The slough is usually slow in coming away, owing to the direction of the connective tissue and elastic fibres which bind it to the underlying structures. This last stage lasts from one to three weeks. The process is more rapid in infected burns and the depth of this burn will depend upon the degree of heat to which the part was subjected, the length of time the heat was applied, and several other factors. The danger of infection is always great owing to: (a) presence of dead tissue; (b) the low resistance of adjacent sick tissue; (c) the open veins and lymph channels; (d) the adjoining skin which is difficult to sterilize; (e) the discharge of a large amount of serum which forms an excellent culture medium. There may be also severe hemorrhage as in any sloughing wound. The danger of this is greatly increased by infection, which breaks down the thrombi in the veins and arteries. +Stages of Granulation.+ The cavity left by the slough rapidly fills with new granulations. These have a tendency to rise above the surrounding skin.