The period of invasion of the attack differs in some degree in the different classes of cases, but it is generally marked with great precision: even when apparent recovery has been followed by a second attack, the occurrence has in each instance been accurately noted by the sudden appearance of constitutional symptoms (see Case XXXVII). When one of the large veins has been originally affected, the period which elapses before symptoms of infection of the system manifest themselves, is comparatively short (Case I). In cases occurring after child-birth, it is usually longer, extending to the end of the second week. After surgical operations or accidents involving some portion of bone, the access of the disease will be marked by a rigor during the third or fourth week; and finally, when the absorbent system is primarily affected, the period of the occurrence of the constitutional symptoms may be much farther removed from that of the original injury (if any such existed), and is by no means so accurately defined. At the time of the occurrence of the general disturbance of the system, the local injury or wound will generally put on an unhealthy appearance. The skin in the immediate neighbourhood will sometimes assume a dull brownish-red appearance, which will gradually fade into the colour of the surrounding parts. This symptom will usually commence near the termination of the vessels, which are derived from the same trunk as those which supply the injured part. When the original injury is complicated with a wound upon the surface of the body, it will usually become dry and glazed, and the blush upon the skin will commence in its neighbourhood, or a short distance from it, and will usually extend towards the centre of the circulation, without presenting any very defined margin: occasionally it will extend, in the form of erratic erysipelas, over a large part of the body.[32] [32] In a case of fracture of the femur into the knee-joint, I have observed a dark ill-defined erysipelatous blush extend from the affected limb to the body, and thence to the head. Purulent deposits formed in various parts of the body, of which the patient died. IX. The commencement of constitutional disease, after direct infection of the blood, is marked by a sudden change in the manner and appearance of the patient; a severe rigor is usually the most prominent symptom, and is followed by much febrile excitement, or by extreme depression; a very peculiar heat of skin (Case XXII) will sometimes be present, while, at other times, the surface will be covered by a profuse clammy perspiration. The rigor may be repeated at irregular intervals, but occasionally it will recur about the same hour for three or four days in succession (Case XXXVII); and in a few instances it will not be observed at all.