GENERAL CHARACTERS OF SPIROCILETES. 33 



days or so, when multiplication of the spirochaetes is 

 found to have taken place. An odour of sulphureted 

 hydrogen is evolved, which may be compared with 

 the foetid odour produced by the organisms of Vin- 

 cent's angina. Schereschewsky found that forms 

 resembling Sp. refringens first developed and after- 

 ward characteristic pallidce. Inoculation of animals 

 with the cultures was unsuccessful. 



Levaditi and Stanesco also record successes in culti- 

 vating Sp. gracilis and Sp. balanitidis in a somewhat 

 similar way. In the case of the latter organism they 

 first inoculated tubes of horse-serum and then made 

 sub-cultures in collodion sacs containing this serum, 

 placed in the serum tubes. They noted that multi- 

 plication of the spirochaetes only occurred when the 

 media were liquefied by the action of proteolytic 

 bacteria an example of symbiosis which they compare 

 with that needed for the cultivation of amoebae. 1 



Most recently of all Bruckner and Galacesco have 

 grown Sp. pallida on coagulated ascitic fluid and have 

 successfully inoculated rabbits with sub-cultures made 

 a month after the material had been sown on artificial 

 medium. 



MULTIPLICATION AND DEVELOPMENT. 



Much controversy has centred round the question of 

 the mode of division of spirochaetes, large and small. 

 Perrin described longitudinal division in Sp. balbianii, 

 and Keysselitz in Sp. anodontcs; and I have seen what 

 appeared to be this process taking place in the latter. 

 Schwellengrebel believes that transverse division is the 

 rule in Sp. balbianii, and Schellack finds it in Sp. ano- 

 dontcs (Fig. 28) and in other forms. Among the smaller 



'The "symbiotic" bacteria probably serve as food for the 

 amoebse, which need solid pabulum. 



