530 HILDA HEMPL HELLER 



by strict morphologists (Zopf, Fischer) entirely independently 

 of any physiological criteria, and in this way was quite justifi- 

 able because by its use a superficially consistent division could 

 be made. The rods which did not swell at sporulation formed 

 one group, those which did swell formed another. But Kruse 

 and the Committee have superimposed upon this type of classi- 

 fication a physiological one, and the result is a division that it 

 is impossible to carry out. Probably more aerobic rods fail to 

 swell at sporulation than do anaerobic rods, but the exceptions 

 to this rule are so numerous on both sides as to render worse 

 than useless the employment of the morphological character in 

 connection with the physiological one. The reader is referred to 

 the illustrations given by Ford and his co-workers and by von 

 Hibler (1908) and by the Medical Research Committee. 



The position of the spore has been used by several authors in 

 subdividing the anaerobes. Species of anaerobes have very 

 characteristic ways of sporulating. But the position of the spore 

 may vary in one species within limits wide enough to render its 

 use exceedingly inadvisable as a character for the grouping of 

 genera. One ma}'- take as a single illustration the behavior of 

 a pure strain of vibrion septique. Vegetative forms are fairly 

 uniform on most media. Sporangia, however, show in their 

 variations all the characteristic forms described by Fischer, by 

 the Committee, and by Buchanan. They are, on meat medium 

 (forty hours' culture), usually thickened in the center with the 

 typical form of Clostridia. But some rods may contain spores 

 and still have parallel sides, and forms with sub-terminal and 

 terminal spores are nearly always to be found. On serum media 

 the vegetative rods may vary greatly in their proportions, the 

 sporangia assume many fantastic shapes, and ''drumstick" 

 forms are common. On the liver of animals the vegetative rods 

 form enormous thick filaments : some strains may sporulate with- 

 out at all changing their outline or may form Clostridia, and 

 some, identical with the first in morphology on ordinary media, 

 may, on the liver of animals, show club-shapes that resemble the 

 clubs formed by the actinomycetes, while others form great 

 globoid masses, terminally or mesially placed in the rods. Rarely 



