IMMUNITY AND SUSCEPTIBILITY. 75 



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. 



An interesting communication upon phagocytosis is 

 that of Bordet, whose experiments seem to show that the 

 lack of disposition to take up bacteria on the part of the 

 leucocytes may depend upon negative chemotaxis. He 

 found that when a guinea-pig became very ill after the 

 intraperitoneal introduction of a streptococcus of mild 

 virulence, if an injection of a culture of Proteus vulgaris 

 was given, the leucocytes, which had steadily refused to 

 take up the streptococci, seized upon the bacilli with 

 avidity. This seems to show that a chemical, or other 

 negative, or inhibitory influence felt by the leucocyte, 

 prevents it from taking up all the bacteria that come 

 within reach. 



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, conspicuous 

 among whom is Nuttall, have shown that freshly drawn 

 blood, blood-plasma, defibrinated blood, aqueous humor, 

 tears, milk, urine, and saliva possess marked destructive 

 influence upon the organisms 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- 



