THE HIGHER BACTERIA 15 



takes place as among the bacilli, but in some of the non- 

 -cptate forms a longitudinal fission may occur. In some species 

 endogenous sporulation has been observed. 



Three terras are used in dividing this group, to which different authors 

 have given different meanings. These terms are spirillum, spirochaete, 

 vibrio. Migula makes " vibrio" synonymous with " microspira," which 

 la- applies to members of the group which possess only one or two polar 

 fla^clla ; "spirillum " he applies to similar species which have bunches 

 of polar Hagella, while " spirochsete " is reserved for the long unHagellated 

 spiral cells. Hueppe applies the term " spirochsete " to forms without 

 endospores, " vibrio " to those with endospores in which during sporula- 

 tion the organism changes its form, and "spirillum" to the latter 

 when no change of form takes place in sporulation. Flugge, another 

 systematist, applies " spirochsete " ancl "spirillum" indiscriminately to 

 any wavy or corkscrew form, and "vibrio" to forms where the undula- 

 tions are not so well marked. It is thus necessary, in denominating such 

 a bacterium by a specific name, to give the authority from whom the 



name is taken. 







Within recent years great doubt has arisen as to whether many 

 of the non-septate spirillary forms, e.g. Spirochcete pallida, are 

 to be looked on as bacteria at all, the view being taken that 

 in, it may be, many cases they represent a stage in the life 

 history of what are really protozoa. The ultimate classification 

 of this group of bacteria must thus be left an open question, 

 and at present it is convenient to denominate the non-septate 

 spiral rods Spirochcete, and those whose vital unit is a single 

 curved rod Spirilla, 



II. The Higher Bacteria. These show advance on the lower 

 in consisting of definite filaments branched or unbranched. In 

 most cases the filaments at more or less regular intervals are 

 cut by septa into short rod-shaped or curved elements. Such 

 elements are more or less interdependent on one another, and 

 special staining methods are often necessary to demonstrate the 

 septa which demarcate the individuals of a filament. There is 

 further often a definite membrane or sheath common to all the 

 elements in a filament. Not only, however, is there this close 

 organic relationship between the elements of the higher bacteria, 

 but there is also interdependence of function ; for example, one 

 end of a filament is frequently concerned merely in attaching 

 the organism to some other object. The greatest advance, how- 

 ever, consists in the setting apart among most of the higher 

 bacteria of the free terminations of the filaments for the produc- 

 tion of new individuals, as has been described (p. 5). There 

 are various classes under which the species of the higher bacteria 

 are grouped; but our knowledge of them is still somewhat 



