KELATION OF PATHOGENIC TO SEPTIC BACTERIA. 3 



purely local effect of the introduction of a pathogenic organism. 

 And it will be necessary to postulate at least this of a would- 

 be pathogenic organism, viz. that its effect after its introduc- 

 tion into an animal should be local, but need not be so if 

 general. 



As is well known, Professor v. Nageli is a firm advocate of 

 the " sporting'^ of harmless saprophytes, they becoming con- 

 verted under certain conditions into pathogenic organisms. 

 But, on the other hand, Professor v. Nageli also maintains that 

 pathogenic bacteria may become converted into harmless sapro- 

 phytes. His views are stated with great clearness in his work, 

 ' Die niederen Pilze/ &c., Munich, 1877. From many years' 

 studies, carried on with patience, and after a strictly experi- 

 mental method, he arrived at these important conclusions. 



Professor v. Nageli makes the very widest allowance for 

 bacteria, inasmuch as a harmless form, when brought under 

 suitable conditions, may become the origin of an infectious dis- 

 ease, may through generations retain this power, and when 

 again placed under different conditions may change into an 

 inactive form. 



Dr. Hans Buchner, a pupil of v. Nageli, and working under 

 this latter's directions, put these general statements to a special 

 test, and succeeded, or maintains to have succeeded, in con- 

 firming them. He claims to have succeeded in changing, by 

 successive artificial cultivations under constantly varying con- 

 ditions, the Bacillus anthracis, of previously deadly power, 

 into a perfectly inactive and harmless bacillus, which in mor- 

 phological respects appeared then identical with the motile 

 Bacillus subtilis (Cohn) of hay infusion. But he also 

 thinks he has succeeded, what is of even greater and more 

 fearful consequence, in transforming, through artificial cul- 

 tivations under ever varying conditions, the notoriously 

 harmless Bacillus subtilis of hay infusion into deadly 

 Bacillus anthracis. 



Dr. Buchner's paper, " Ueber d. exper. Erzeugung d. Milz- 

 brandcontag. aus d. Heupilzen . . . .," which gives the results 

 of a very large number of observations, is published in the 



