CHAPTER VI 



SOME OBSERVATIONS OF A DIPHTHEROID 

 BACILLUS 



It will be remembered that Clark and Ruehl observed that the 

 diphtheria and diphtheria-like bacilli showed a decrease in size dur- 

 ing the early stages of growth, followed by a gradual increase. Al- 

 bert, on the other hand, claims that the diphtheria bacillus increases 

 in size during the first four hours of growth, remains stationary 

 for about twenty hours, and then gradually decreases. This, how- 

 ever, I cannot confirm, as I find that during the actual growth 

 period they become smaller. This group therefore deserves some 

 particular study, but is not well suited for the type of work here 

 reported because most of the members of the group are very small 

 and are grown with some difficulty on artificial media. I was for- 

 tunate, however, in finding a saprophytic organism which seems 

 to possess the characters of the Corynebacteria, that is quite large 

 and could also be grown fairly readily. It is a red chromogen and 

 was isolated from lake water. Since this organism is apparently a 

 new species it will be described in some detail. 



In morphology it resembles the Corynebacteria in the possession 

 of very prominent metachromatic granules, in pleomorphism which 

 is very prominent in old cultures, in a tendency toward a paHsade 

 arrangement of the cells at some stages of growth, and in the fact 

 that during the early stages of growth the cells are much smaller 

 than they are later. The length of the cells on ordinary agar may 

 be found in Table XX. In other media, particularly Loeffler's blood 

 serum and dextrose agar, they may be much larger. The diameter 

 does not vary so much as the length. The cells also vary consider- 

 ably in form. They are generally cylindrical with rounded ends; 

 when in pairs or chains the opposed ends are flattened. According 

 to the medium and age of the culture they vary from short oval 

 cells, sometimes almost spherical, to long filaments. In old cultures, 

 cells of irregular shape appear. In young cultures, particularly on 



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