Bacteria frequently gain access to the circulation. However, there is still a marked difference of opinion as to how frequently this occurs and how serious this invasion is, some believing that it is a phenomenon always accompanied by marked systemic disturbance, others that if the number of bacteria is small, the body rids itself of the invaders without the aid of any general reaction. It is known that microorganisms are eliminated from the circulation chiefly by way of the kidneys and of the liver, but it is not known what the determining factors are. Are the bacteria filtered from the blood stream by means of the tissues, in the same way as inert foreign particles; for example, as would be the case if an equal amount of egg white had found its way into the blood, or does this mechanical process play a rôle secondary to other finer defensive processes?
HESS AF. THE RELATION OF THE VIRULENCE OF THE TUBERCLE BACILLUS TO ITS PERSISTENCE IN THE CIRCULATION. Arch Intern Med (Chic). 1912;X(6):577-584. doi:10.1001/archinte.1912.00060240059004