RELATION OP PATHOGENIC TO SEPTIC BACTEEIA. 5 



various " generations." Thus he found (p. 384) that minute 

 quantities of the first cultivation proved effective, whereas the 

 second, third, and fourth, in small quantities, proved ineffectual ; 

 but the fifth cultivation proved effective in large quantities : 

 the sixth was ineffective. In a series of cultivations in meat 

 extract, peptone, and sugar, the second cultivation proved 

 active; the third and fourth inactive; the fifth active; the 

 seventh, eighteenth, and even the thirty- sixth generation proved 

 active. From all these and similar observations Buchner de- 

 duces that the Bacillus anthracis undergoes a gradual 

 change, by which sooner or later it is rendered altogether 

 harmless and inactive. This change is, however, not one of 

 morphological character. I shall, further below, when de- 

 scribing my own observations on these subjects, have to return 

 to Buchner's observations, and I shall then show that all his 

 facts are easily explained by the aid of my own observa- 

 tions, but not by the theory of a gradual diminution of 

 activity of the Bacillus anthracis. There is such a thing 

 as a real diminution of activity of the Bacillus anthracis in 

 artificial cultivations; the inactivity on white mice of some 

 cultivations of the Bacillus anthracis and not of others is 

 due to a variety of circumstances, one of which, at any rate, is 

 this, the absence of spores. If Buchner had tested his cul- 

 tivations on guinea-pigs or rabbits he would have obtained 

 altogether a different result, always supposing that he worked 

 with pure cultivations of Bacillus anthracis. 



Koch ('Zur Aetiologie d. Milzbr.,' p. 22 at passim) con- 

 siders it probable that Buchner's uncertain and unequal results 

 are explained by the fact that his (Buchner's) cultivations not 

 being absolutely guarded from contamination with other non- 

 pathogenic bacilli, he may have had, and probably did have, 

 in some of his cultivations the Bacillus anthracis, originally 

 sown, diluted, or altogether suppressed by the overgrowth of 

 the non-pathogenic bacillus. With Koch I fully think this 

 objection well justified, especially since Buchner does not admit 

 a difference between non-moving non-pathogenic bacilli and 

 the non-moving Bacillus anthracis. 



