DIPHTHEROID ORGANISMS 9 



The rightful name for this species is Corynebacterium pseudodiphtheriticum 

 (Hofmann-Wellenhof). It is questionable, however, if we can retain this name 

 for all diphtheroids which are morphologically and culturally like the one 

 described by v. Hofmann. Recent studies show that there are different species 

 of saprophytic diphtheroids which conform to the type characters, yet are not 

 found in the nose or throat. At the close of this communication we shall 

 describe a few such strains which have been isolated from widely varying 

 sources. 



B. PSEUDODIPHTHERITICUS ALCALIFACIENS 

 .B. PSEUDODIPHTHERITICUS ACIDUM FACIENS 



These names were applied by 'Kurth to diphtheroid organisms which he found 

 to be avirulent, and were capable of producing, respectively, a weakly alkaline 

 and an acid reaction in sugar broth. The alcalifaciens species conforms to the 

 following description : No granules, short forms on serum with white growth, 

 abundant growth in bouillon with clouding, no acid produced in sugar broth. 



This description, although meager, suggests that Kurth was undoubtedly 

 dealing with the type Hofmanni. B. alcalifaciens should lapse into synonymy 

 with this species. As for the B. pseud, acidum faciens a new species is hardly 

 justified in view of the fact that avirulent diphtheroids differ in their fermenta- 

 tive properties in various sugars. Moreover the description is incomplete. 

 Apart from the interest which attaches to the first attempt at classification 

 from the fermentation standpoint, these two species have no particular value. 



B. XEROSIS (NEISSER AND KUSCHBERT) MIGULA 



Club-shaped, plump, and longer septate forms. On blood serum terminal 

 swellings never noted. Gram-positive, polar bodies sometimes visible, no 

 growth below 25 C, no clouding in bouillon, but granular sediment is formed. 

 Distinguished from pseudodiphtheria by its ability to grow only above 25 C. 



One point needs slight modification in this description of B. xerosis, namely, 

 that of temperature requirement. On certain mediums, such as ascitic dextrose 

 agar we have noted growth of 12 strains of diphtheroids which were isolated 

 fiom the eye. These organisms complied with the description given for 

 B. xerosis as regards morphology and fermentative properties in different car- 

 bohydrate broths. Some of the strains developed very slowly at temperatures 

 ranging from 18-25 C., showing delicate growth on slant mediums after 4 

 days. Eisenberg states that B. xerosis grows only at body temperature. 



B. SEPTATUM GELPKE 



Nonmotile, gram-positive, club-shaped forms on serum. Young cultures 

 show polar staining, no spores. Grows on serum with a delicate yellowish 

 dry appearance. In bouillon no clouding occurs but a granular flaky deposit 

 is visible. Does not grow at temperatures below 28 C. Is to be distinguished 

 from other organisms of the group by this property. Associated with conjunc- 

 tival inflammation "schwellungskatarrh." 



A comparison of the 2 organisms just described makes it appear questionable 

 that we are dealing with a distinct species in B. septatum. This organism 

 which appears to be identical with B. xerosis is, like the latter, not necessarily 

 associated with a conjunctivitis for B. xerosis has been isolated frequently 

 from normal eyes. Zinsser is of the opinion that the B. xerosis is a harmless 

 parasite which may occur more often in the slightly inflamed than in the nor- 

 mal conjunctiva. The term septatum is not especially characteristic for diph- 



