356 ACTINOMYCETES 



cultures. According to 0rskov, fragmentation begins at the center 

 of the colony and proceeds peripherally. After the mycelium has 

 split into elements of fairly uniform length, these undergo post- 

 fission movements of precisely the same kind as those shown by the 

 diphtheroid bacteria, one element moving through an arc to lie at an 

 angle with the adjacent element. This 0rskov refers to as angular 

 growth. It is particularly characteristic of the pathogenic species, 

 and may be considered further evidence of a relationship to bacteria. 

 Such a zigzag arrangement of the elements produced by fragmenta- 

 tion of the mycelium is also characteristic of G. candidum. 



I V i ^ 



r K V- V.- 



/ 



V:./ 





77^WL^^ 





h 





Fig. 129. Diagram showing origin of bacterial forms from mycelium in 

 Nocardia: a, continuous mycelium; b, fragmentation; c, post-fission move- 

 ments lead to "angular growth." 



When smear preparations are made from fragmented cultures of 

 actinomycetes, naturally the arrangement of the mycelial fragments 

 is disturbed and they become irregularly scattered. Here and there 

 will be found two cells in a V-shaped arrangement. The appearance 

 of the slide is that of a rather pleomorphic bacterium, such as the 

 diphtheroid organism. If in addition some conidia have been 

 formed, these will appear very much like cocci in chains, and the 

 resemblance to a smear preparation of mixed bacteria is very close 

 indeed. 



In preparations stained by certain methods, deeply stained gran- 

 ules may sometimes be demonstrated. There has been some discus- 

 sion of whether or not these are to be considered nuclei. They may 

 " be„cornpletely absent in the younger mycelium, may first appear as 

 _smali isolated granules, and may occur as numerous large masses in 

 '/the older mycelium. IVjogt authors ar.e. inclined to interpret them as 

 , volutin, and it is certain that most .ofjt.hese i)3odies are volutin gran- 

 ules. It has been demonstrated, however, jn recent years that some 

 of these are nuclei. Drechsler,*^ some twenty-five years ago, inter- 

 preted bodies which he found in developing conidia as nuclei but 



