14 BACTERIOLOGY 



6. THE FORMATION OF GONIDIA 



In the higher bacteria, as in Mycobacteriaceae, the cells or fila- 

 ments may undergo multiple segmentation, resulting in the 

 formation of numerous short rods or coccoid forms, which par- 

 take of the nature of gonidia. 



They may be termed resting bodies, inasmuch as they lie dor- 

 mant for a greater or less period until a favorable environment 

 causes them to elongate and produce the original vegetative form 

 from which they sprang. Certain bacteriologists have considered 

 many of these so-called gonidia as degeneration forms ; but it is 

 more likely that they are distinct morphologic elements, inas- 

 much as degenerative elements could not be expected to produce 

 new vegetative cells. Thus, if one has ever searched in old 

 tuberculous lesions for the presence of tubercle bacilli, one must 

 have been struck with the complete absence of typical bacilli ; 

 and yet it is well known that such tuberculous matter when 

 injected into guinea pigs will produce tuberculosis. The only 

 explanation is that these granular particles are resting bodies of 

 thfe nature of gonidia, which are capable of reproducing the 

 species. The great resistance of diphtheria germs to unfavor- 

 able conditions, as drying, conditions which rapidly destroy the 

 vegetative cell, makes it likely that the granular segments which 

 they often produce are of the nature of gonidia. According to 

 A. Coppen Jones, tubercle bacilli produce gonidia. These 

 stain more deeply than the vegetating portions, and more 

 strongly resist the decolorizing action of acid. They are shown 

 in Fig. 7, E. In Streptothrix we have frequent instances of the 

 formation of gonidia. In Streptothrix bovis the filaments or 

 chains of iilaments which are enclosed in a common capsule 

 undergo multiple segmentation, producing coccoid bodies which 

 at first remain enclosed within the sheath, and finally escape 

 from the dissolution of the latter as seen in Fig. 7, A. In 

 Streptothrix chromogena, the branched filaments show multiple 



