#Pyæmia# is a form of blood-poisoning characterised by the development of secondary foci of suppuration in different parts of the body. Toxins are thus introduced into the blood, not only at the primary seat of infection, but also from each of these metastatic collections. Like septicæmia, this condition is due to pyogenic bacteria, the _streptococcus pyogenes_ being the commonest organism found. The primary infection is usually in a wound--for example, a compound fracture--but cases occur in which the point of entrance of the bacteria is not discoverable. The dissemination of the organisms takes place through the medium of infected emboli which form in a thrombosed vein in the vicinity of the original lesion, and, breaking loose, are carried thence in the blood-stream. These emboli lodge in the minute vessels of the lungs, spleen, liver, kidneys, pleura, brain, synovial membranes, or cellular tissue, and the bacteria they contain give rise to secondary foci of suppuration. Secondary abscesses are thus formed in those parts, and these in turn may be the starting-point of new emboli which give rise to fresh areas of pus formation. The organs above named are the commonest situations of pyæmic abscesses, but these may also occur in the bone marrow, the substance of muscles, the heart and pericardium, lymph glands, subcutaneous tissue, or, in fact, in any tissue of the body. Organisms circulating in the blood are prone to lodge on the valves of the heart and give rise to endocarditis. [Illustration: FIG. 13.--Chart of Pyæmia following on Acute Osteomyelitis.] _Clinical Features._--Before antiseptic surgery was practised, pyæmia was a common complication of wounds. In the present day it is not only infinitely less common, but appears also to be of a less severe type. Its rarity and its mildness may be related as cause and effect, because it was formerly found that pyæmia contracted from a pyæmic patient was more virulent than that from other sources. In contrast with sapræmia and septicæmia, pyæmia is late of developing, and it seldom begins within a week of the primary infection. The first sign is a feeling of chilliness, or a violent rigor lasting for perhaps half an hour, during which time the temperature rises to 103°, 104°, or 105° F. In the course of an hour it begins to fall again, and the patient breaks into a profuse sweat. The temperature may fall several degrees, but seldom reaches the normal. In a few days there is a second rigor with rise of temperature, and another remission, and such attacks may be repeated at diminishing intervals during the course of the illness (Figs. 12 and 13). The pulse is soft, and tends to remain abnormally rapid even when the temperature falls nearly to normal.