But cases of septicaemia sometimes occur when the entire procedure appears to have been blameless and the question arises whether in these cases the origin of the blood poisoning does not lie in the patient. The whole subject is bound up with those of susceptibility and immunity (q.v.), the behaviour of micro-organ isms in producing infective disease (see BACTERIA AND DISEASE) and the bacterial flora of the animal body, particularly the alimen tary tract. It may be granted that septicaemia can only occur if the causal organisms have gained access to the blood, that in vasion may take place with a minute inoculation, if the sus ceptibility of the patient be very great (i.e., his defensive mechanisms be impaired) or the organisms be highly virulent and that probably the operation wound or the puerperal uterus is the seat of invasion, the organisms being introduced from with out. Nevertheless it is not impossible that operation or parturi tion has impaired the patient's natural defences and that the invading micro-organisms have come from the intestines, where streptococci normally exist in great numbers and several varieties, or from such a focus as a septic tooth cavity, middle ear disease, chronic appendicitis, a gonococcal infection or even endocarditis. Such foci have long been recognized as occasional starting points of pyaemia.
Pyaemia differs from septicaemia chiefly in the facts (I) that the invading organisms are pyogenetic, usually staphylococcus pyogenes aureus, but sometimes varieties of streptococci or diplo coccus pneumoniae; (2) that the infection is rarely so great that micro-organisms can be recovered from the circulating blood by bacteriological culture; (3) that abscesses are formed where the bacteria become lodged, that is, in the smaller arterial ramifications often in muscles, around joints and, secondarily, from those foci in the lungs and pleural cavities. A special variety of pyaemia occurs in ulcerative endocarditis in which particles of the inflammatory material on the mitral or aortic valves with the entangled micro-organisms are carried away in the blood stream.
Symptoms and existence of sapraemia or septicaemia is signalized by rise of temperature in a patient who has a wounded and absorbing surface (i.e., within the first three days after operation, injury or parturition). The extent of rise varies, temperatures of I o I ° and 102° F being common; there after the temperature may remain high with irregular but small remissions or there may be daily remissions over a large range of degrees, e.g., evening 103° F, morning 99° F. Probably these differ ences depend upon the amount of poison being formed and ab sorbed from time to time. In pyaemia temperature conditions are similar but obviously pyaemia cannot be diagnosed before the septic abscesses have begun to form ; this is generally first shown by the appearance of a painful and reddened focus. The primary wound usually becomes red and oedematous, the lymphatic glands draining the area are enlarged and painful and may suppurate and there may be lymphangeitis (see LYMPHATIC SYSTEM, DISEASES OF).
As regards treatment, apart from the removal of dead material by drainage and lavage which is rapidly effective in sapraemia treatment of this condition is usually unnecessary. In septicaemia and pyaemia the sole rational treatment is by antisera (see SERUM THERAPY). Full doses of a polyvalent antistreptococcus serum should be given in all cases and the strength of the patient should be husbanded to the fullest possible extent. The conditions are extremely grave, but hope should never be abandoned so long as life remains. (W. S. L.-B.) SEPT (set or sept), a clan, applied to the families of Ireland, and sometimes used of East Indian tribes (probably Lat. seeptum, an enclosure).