156 AIDS TO BACTERIOLOGY 



Spirillum Tyrogenum. 



(Syn., Deneke's cheese bacillus.) Forms no indole, is 

 but feebly pathogenic for laboratory animals, and does 

 not develop readily at blood-heat. 



Spirillum Rubruin. 



This organism, which is non-pathogenic, is found in 

 water and garden earth. In broth long threads, with up 

 to fifty twists, are formed. The shorter spirals are very 

 motile. Colonies on gelatin out of contact with air and 

 those on potato are red, and a red sediment is produced 

 in broth. 



Other spiral organisms, sometimes classed as Spirilla, 

 are more correctly placed among the Protozoa, and will 

 be dealt with later. 



CHAPTER XIV 

 THE TRICHOMYCETES 



THE Trichomycetes are thread-forming organisms and 

 form a group intermediate between the Schizomycetes 

 and the Hyphomycetes. Much confusion exists as to the 

 terminology of the class, the same term being used in 

 different senses by authors. The following classification 

 is convenient: 



Leptothrix: No branching. 



Cladothrix: ' False ' branching. 



Nocardia, or Streptothrix : True branching, with forma- 

 tion of rounded bodies, regarded as spores. 



Aetinomycosis. 



Morphology. Actinomyces, or ray-fungus, is a strepto- 

 thrix occurring in three types in the colonies as they 

 grow in the tissues namely, filaments, cocci, and clubs. 

 The filaments (seen better in cultures) are thin, measuring 

 about 0-5 /* across, and are often of great length. The 

 central protoplasm is enclosed in a sheath ; the filaments, 

 particularly in the centre of a colony, interlace, forming 

 a network. In oklor filaments the protoplasm may be 

 segmented, giving rise to a streptococcal appearance. 

 These bodies are regarded as gonidia. The clubs are 



