276 MANUAL OF BACTERIOLOGY. 



that the spiral forms are in reality not separate organisms but 

 represent stages in the cycle of development of the fusiform 

 bacillus which is polymorphous to a very marked degree, 

 showing short bacilli, long filaments and spirals. The bacilli 

 form spores, usually one spore to each bacillus, sometimes two. 

 The filaments are either straight or wavy. The spores retain 

 the stain when treated as in staining tubercle bacilli and de- 

 colorized with i per cent, sulphuric acid. The cultures upon 



c 



TIG. 61. Spirilla from swamp water showing flagella (Loffler 

 stain). (X 1000.) 



which Tunnicliff's observations were made were obtained from 

 three normal throats, but the culture corresponded in all 

 respects with those obtained by her and Weaver already 

 mentioned. 



Higher Bacteria. Certain organisms (beggiatoa, thiothrix 

 leptothrix, cladothrix, actinomyc.es or streptothrix) of more 

 complicated structure than most bacteria, but resembling them 

 in many respects, are called "higher bacteria." They consist 

 of definite filaments which are usually made up of rod-shaped 

 elements, but the relation between these elements is very intimate. 



