BACTERIA IN DISEASE. 



the circulation. We see typical toxemias in diphtheria and 

 tetanus. In surgery the term sapremia is used to cover a 

 similar condition of affairs when the absorption proceeds 

 from a wound or denuded surface, as may happen in the 

 puerpural uterus. 



Septicemia. In septicemia there is not only absorption 

 of the bacterial poisons, but the bacteria have invaded the 

 living tissues. Bacteriologists usually employ the word 

 septicemia to describe the wide dissemination of bacteria 

 through the body and the presence of a large number of 

 them in the circulating blood. In this sense septicemias 

 are commoner in lower animals than in man; anthrax and 

 infection with micrococcus lanceolatus would be examples. 

 Typical septicemias in man are found in relapsing fever and 

 certain cases of bubonic plague. For pyemia, see the article 

 on Suppuration, Part IV. 



The principal agencies in effecting recovery from in- 

 fectious diseases are the presence or formation in the body 

 of substances which destroy bacteria (lysins), the develop- 

 ment of new substances which also neutralize their action 

 (antitoxins), and their destruction by the cells of the body 

 (phagocytosis). These phenomena are discussed in the 

 chapter on immunity. A factor of less importance is the 

 elimination of bacteria by the excretory organs. Experi- 

 ments on animals indicate that bacteria which have been 

 injected into the body do not appear in the urine until they 

 have damaged the structure of the kidney. In typhoid fever, 

 the bacilli of typhoid may occur in the urine in great num- 

 bers; the condition of the kidney in the generality of such 

 cases has not thus far been determined. The extent to 

 which the excretory organs act in eliminating bacterial 

 toxins is not yet known. Some bacteria, as has already 

 been stated, may, in the end, produce substances that are 

 inimical to their own growth. 

 '5 



