INFECTION AND INTOXICATION. 87 



species of bacteria, some having a definite selective affin- 

 ity for certain cells, as tetanus toxin for the motor nerve 

 cells. The action of certain toxins may be enzymic. 



lilimination of Bacteria from the Blood. — According to 

 Kruse, 1 the entrance of bacteria into the circulation is 

 possible by — 



1. Passive entrance of bacteria through the stomata of 

 the vessels where the pressure of the inflammatory exu- 

 date is greater than the intravascular pressure. 



2. Entrance of the bacteria into a vessel in the bodies 

 of leukocytes that have incorporated them. 



3. Actual penetration of the vessel wall by the growth 

 of the micro-organism. 



4. Entrance into the vessels via the lymphatics either 

 passively or in leukocytes. 



In all probability non-pathogenic bacteria, and path- 

 ogenic bacteria which for any reason, such as the occur- 

 rence of immunity from developed antitoxins, etc., have 

 become non-pathogenic for the animal, are disposed of in 

 much the same manner as inert minute particles injected 

 into the circulation. Siebel has shown, regarding them, 

 that they accumulate in the fine capillaries, especially in 

 the lung, liver, spleen, and bone marrow, and are slowly 

 transferred to the surrounding tissues, either to be col- 

 lected in the connective tissues, carried to the lymphatic 

 nodes, excreted with bile, succus entericus, etc., or dis- 

 charged from the surface of the mucous membranes, 

 pulmonary alveoli, tonsils, etc. They also escape from 

 suppurating wounds to which they may be carried by 

 leukocytes. No doubt many of the bacteria, being organ- 

 ized particles, undergo dissolution in the body without 

 excretion. Siebel did not find that the particles were 

 excreted by the kidneys. Wyssokowitsch is in accord 

 with Siebel, and has shown experimentally that the kid- 

 ney rarely eliminates bacteria. Cavazzani found that 

 unless the renal epithelium was injured no bacteria 

 escaped from the blood. 



1 Fliigge, Die Mikroorganismen, vol. i., p. 271. 



