In 1914, Schottmueller wrote, "Septicemia is a state of microbial invasion from a portal of entry into the blood stream which causes sign of illness." The definition did not change significantly over the years because sepsis and septicemia were considered to refer to a number of ill-defined clinical conditions in addition to bacteriemia. In practice, the terms were often used interchangeably; however, less than one half of the patients who have signs and symptoms of sepsis have positive blood culture results.