ADAPTIVE CHANGES OF BACTERIAL CULTURES. 7 



Second : that the influx of leucocytes take place with a certain 

 regularity and in a gradual and progressive manner. Selection 

 requires a certain time. It is in those places in an immunized 

 animal where the influx of leucocytes occurs slowly, for example, 

 in the anterior chamber of the eye, that the vibrio Metchnikovi 

 acquires the most extreme virulence. It has been noted in referring 

 to Metchnikoff's work that the vibrio obtained in this manner is the 

 most active, killing the guinea-pig in 6 hours. 



Another fact of Metchnikoff's is very similar. Anthrax is more 

 deadly for the pigeon when injected into the aqueous humor than 

 elsewhere. It will be recalled also that with some organisms inocu- 

 lation into the circulation is much less dangerous than into the 

 connective tissue. 



This ends our account of the vibrio Metchnikovi for the present; 

 we shall later return to it: 



Not all organisms, as, for example, the bacillus of swine plague 

 (rouget du pore), acquire the same virulence when passed through 

 vaccinated or more or less refractory animals. 



New studies to determine whether a culture subjected to various 

 conditions becomes modified in respect to its chemiotactic power 

 and the toxicity of its secretions are in progress. 



