xvii.] SEPTIC AND PATHOGENIC ORGANISMS. 213 



he saw it assume gradually the properties of hay bacillus. 

 Thus he saw that its mode of growth gradually changed, 

 inasmuch as instead of forming, as the typical bacillus 

 anthracis does, fluffy convolutions at the bottom of the fluid- 

 nourishing medium, it gradually showed a tendency to stick 

 to the glass and to the surface of the fluid, and to form a 

 sort of pellicle just like the hay bacillus does. This I consider 

 to be an erroneous interpretation of an easily explained and 

 simple fact. It does not want any of the many successive 

 generations of bacillus anthracis, in which Buchner says he 

 has achieved this transformation; it simply requires two 

 nourishing fluids in both of which the bacillus anthracis will 

 thrive well, but which fluids differ in specific gravity. Let 

 Buchner do as I have done, let him take two test-tubes, both 

 containing sterile broth, but in one the broth concentrated, 

 in the other dilute. Let him inoculate the two test-tubes 

 with bacillus taken from the same blood, say of a guinea-pig 

 dead of anthrax, let him place them in the incubator at a 

 temperature of 35 to 38 C. After two or three days, and 

 more decidedly later, he will notice this very difference in 

 the aspect of the cultures that he lays so much stress on 

 as indicating a change in the physiological character of the 

 bacillus. One test-tube, containing the dilute broth, shows 

 the typical fluffy convolutions at the bottom of the fluid ; while 

 the other, containing concentrated broth, shows a distinct 

 attempt at the formation of a pellicle. Let him now take 

 out a droplet from this second test-tube and inoculate with 

 it two test-tubes of the same nature as above, i.e. one 

 containing concentrated broth, the other dilute broth. After 

 two or three or more days of incubation he will find exactly 

 the same differences as above. 



Buchner states that the bacillus anthracis when carried 

 through a large number of successive cultures, at a tempera- 



