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. 



CHLAMYDOBACTERIACE^ 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 NatUrlichen 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 



