404 AGTINOMYCETES. 



nished that these organisms, which in their extreme forms 

 differ widely from the diphtheria bacillus, are connected 

 with it genetically. Therefore there are no essential reasons 

 for regarding these forms simply as atypical diphtheria 

 bacilli in the broader sense. 



On the other hand, it is not possible to separate them 

 naturally into definite varieties by the side of diphtheria 

 bacilli, any more than this is possible in the forms of the 

 Bact. coli and water vibrios. It is customary at present 

 to dispose of this by designating the luxuriantly, succu- 

 lently, and rapidly growing non-virulent forms as Coryne- 

 bacterium pseudodiphtheriticum (Hofmann-Wellenhof) 

 Lehm. and Neum., the scantily and delicately growing 

 forms as Corynebacterium xerosis (Neisser) Lehm. and 

 Neum., and the other non-virulent forms ^ are pressed 

 into this scheme as well as possible. 



Corynebacterium pseudodiphtheriticum. (Lbffler.) 

 L. and N. 



(Plates 58-60, in part.) 



Pseudodiphtheria bacillus of Loffler. Discovered by 

 von Hofmann-Wellenhof in 1887. Described in detail 

 by Escherich (Aetiol. der epid. Diphth. ), Zarniko (C. B. 

 VI, 153), and Prochaska (Z. H. xxrv, 373). 



Rods, which upon serum are shorter and thicker than 

 true diphtheria bacilli, show less often a tendency to form 

 clubs and segments, but have a tendency to parallel group- 

 ing and are not virulent for guinea-pigs (Escherich). Upon 

 glycerin-agar it grows not alone upon the inoculation line, 

 but in two to four days spreads out over the surface of the 

 agar. It varies from milky white to dirty yellowish or gray, 

 is succulent, and the border is slightly notched (58, iii). 



297). E. O. Neumann (not yet published) found in every case of 

 catarrhal cold, but also in every healthy nose, often very abundant 

 diphtheria-like organisms, sometimes growing luxuriantly, sometimes 

 delicately, mostly producing a little acid and giving only slight 

 granule staining. The virulence has not been investigated. 



' These forms are usually not entirely non-virulent. C. Frankel 

 and others have seen animals die with marasmus a long time after the 

 injection of large doses of bouillon culture. 



