IMMUNITY AND SUSCEPTIBILITY. 67 



tralize the bacterial poisons, and liberate the contesting 

 cells. 



Wyssokowitsch found that saprophytic micro-organ* 

 isms are quickly eliminated from the blood when in- 

 jected into the circulation. This elimination is not 

 by excretion through organs nor by destruction in the 

 streaming blood, but by collection in the small capil- 

 laries, where the blood-stream is slow and where the 

 micro-organisms are taken up by the endothelial cells. 

 Wyssokowitsch found them most numerous in the liver, 

 spleen, and bone-marrow, and found that in these situa- 

 tions they were destroyed in a short time saprophytic 

 in a few hours, pathogenic in from twenty-four to forty- 

 eight hours. Spores of Bacillus subtilis remained as 

 living entities in the spleen for three months. 



4. THE HUMORAL THEORY. It was observed that if 

 anthrax bacilli were introduced into a few drops of 

 rabbit's blood, they were instantly killed. This obser- 

 vation was one of immense importance, and from it and 

 similar observations Buchner deduced the principles of 

 his theory, which teaches that the destruction of patho- 

 genic bacteria in the body is due to the bactericidal 

 action of the blood-plasma, not to phagocytosis; which 

 phenomenon amounts to nothing more than the burial 

 of the dead bacteria in "cellular charnel-houses." The 

 experiments of Buchner and his followers have shown 

 that freshly-drawn blood, blood-plasma, defibrinated 

 blood, aqueous humor, tears, milk, urine, and saliva 

 possess marked destructive influence upon the organ- 

 isms brought in contact with them an influence easily 

 destroyed by heat. 



The apparent paradox of rapid multiplication of an- 

 thrax bacilli in the rabbit's blood enclosed in the rabbit's 

 body, and the reversed action in the test-tube, caused im- 

 mediate and prolonged opposition to the theory. Each side 

 of the question seemed well supported. The phagocytolo- 

 gists, however, showed that bacteria were often injured 

 and their vegetative powers destroyed by sudden changes 



