THE CLASSIFICATION OF BACTERIA 369 



Milk. Slowly peptonized. Good growth in vegetable infusions, of a slightly 

 acid reaction, as hay, potato. Media clear with brownish flocculi, which 

 on the surface are red, often forming a membrane ; the reaction becomes 

 alkaline. 



Pathogenesis. At most only a slight local reaction in rabbits and guinea pigs. 



Habitat. Associated with a warty ulcerative affection of the feet, and rarely 

 of the hands. 



Madura foot. In the lesions no nodular swellings, but in the periphery of 

 the colony a zone concentrically arranged, spindle-shaped elements, prob- 

 ably degeneration forms of the filaments. 



CHLAMYDOBACTERIACEjE Migula 



Filamentous bacteria composed of rod-shaped cells, and surrounded by a dis- 

 tinct sheath. Division of the cells at right angles to the axis of the fila- 

 ments. In Phragmidiothrix and Crenothrix, however, in the formation 

 of gonidia, a division of the cells in three directions of space takes place*. 

 Reproduction by means of gonidia, which are either motile or non-motile. 



I. Cell contents without sulphur granules. 



A. Filaments unbranched. 



1. Cell division takes place only in one direction of space. Leptothrix. 



2. Cell division, before the formation of gonidia, takes place in three 



directions of space. 



a. Filaments surrounded by a delicate, scarcely discernible sheath. 



Phragmidiothrix. 



b. Filaments surrounded by a plainly discernible sheath. Creno- 



thrix. 



B. Filaments show false branchings. Cladothrix. 



II. Cell contents contain sulphur granules Thiothrix. 



LEPTOTHRIX Kutzing 



Phycologia Generalis, 1843, 198. 



Streptothrix Migula: Die Natiirlichen Pflanzenfam., 1895. 



Filaments unbranched, non-motile, enclosed in very delicate or rather thick 

 sheaths, either fixed or associated in slimy masses. The separation of 

 the filaments and the presence of a sheath is demonstrated by special 

 methods of staining. The contents of the filaments become segmented, 

 forming round or ovoid gonidia, which escape from the sheath and de- 

 velop into filaments. Gonidia non-motile. 



2B 



