_Lesions._ Pyæmia may result from a wound or abscess in connection with which will usually be found a vein containing a thrombus more or less softened or liquefied. If from a deep seated injury or from osteomyelitis, the same condition is met with. The thrombus and circulating blood furnish abundance of the infective microbes, and at distant points, in the complimentary circulation, most commonly in the lungs the arteries are found to be the seats of _embolism_ from arrested clots. The arrest always takes place where the vessels are diminished by bifurcation, or the giving off of a considerable colateral trunk, and the appearances will depend on the duration of the embolism. If quite recent, a wedge-shaped mass of tissue supplied by the vessel is ischæmic and pale, its blood passing on into the veins without further arterial supply; if later, this tissue forms an _infarct_ being gorged with deep red or black blood which has filtered in from adjacent anostomosing capillaries and distended those of the exsanguine area. This area becomes of a deep red or black color, consolidated by an exudate of lymph, and rapidly invaded by suppuration. The microbes determine suppuration and softening, first in the clot and intima, and next in the outer coats of the vessel and the surrounding exudate, so that an abscess of variable size may result. Abscesses are usually smaller and more numerous in the acute forms of the disease, and larger and less numerous in the more chronic. Ulcerative endocarditis with coagula on the valves is not uncommon. The spleen is often the seat of small abscesses in the centre of solid exudates, with in many cases softening and enlargement of the organ. The blood tends to retain its normal bright red color, and clots firmly, contrary to the usual condition in septicæmia. _Symptoms._ The formation of emboli and secondary abscess is usually marked by a violent rigor, lasting from a few minutes to an hour and which may be repeated at irregular intervals, serving, in some measure, to distinguish pyæmia from septicæmia. The temperature rises with the rigor, (102° to 105°) but shows marked remissions especially in the morning, when it may not exceed the normal, and rising again with the recurrence of chill or staring coat. The pulse is usually encreased in frequency even during the remissions and is soft and compressible. Remissions may be attended by profuse perspirations or even, in the advanced stages, by fœtid diarrhœa. The breath has a peculiar sweetish or mawkish odor. Blood passed with the fæces may indicate intestinal abscess, and albumen or pus in the acid urine, bespeaks suppurating foci in the kidney. The cloudy mucus from the pelvis of the kidney in the horse must not be mistaken for this. Cough or dyspnœa will indicate abscess of the lungs, and intercostal tenderness, pleurisy.