436 



TR Y-PA NO SO M ID ^ 



Uemarks.— The Spirochaetacea are closely related to the Binu- 

 cleata, and especially to the Trypanosomidse. 



The Treponemata are joined to the spirochaetes because of their 

 general resemblance, though it must be admitted that no nucleus 

 of the nature of the spirochsete nucleus has yet been described, and 

 the spirals are apparently not due to movement. 



The Spirochaetacea are potent factors in the production of disease, 

 for 5. recurrentis is the cause of one type of relapsing fever, S. carteri 

 of another, S. duttoni of another, and S. novyi of yet another, while 

 the Treponemata are the cause of syphilis and yaws. 



The Spirochsetacea may be divided into two families : — ■ 



I. With undulating membrane: Spirochaetidse. 

 ' 2. Without undulating membrane : Treponemidae. 



Spiroehsetidse Ehrenberg, 1883. 



Deflnition.^ — -Spirochaetacea with an undulating membrane. Body 

 may be ribbon-shaped on transverse section. 



Type Species.— S/>2>ocA<^^a plicatilis Ehrenberg, 1833. 



Remarks. — -There is a difference of opinion as to whether these 

 organisms are protozoa or bacteria. At first they Were universally 

 regarded as bacteria, but in 1904 Schaudinn's paper on the leuco- 

 cytozoon in the little owl indicated that this body, after fertiliza- 

 tion in the gut of Culex pipiens and subsequent asexual division, 

 produced a large number of minute forms which he at the time 

 considered to be spirochaetes, and he further concluded that in all 

 probability all spirochaetes Were stages in the life-history of intra- 

 cellular parasites. In 1905, however, he came to the conclusion that 

 the spirochaete forms which he had seen develop from T. ziemanni 

 Were trypanosomes. In fact, there is one great point of difference 

 —the forms which he described possess a distinctly consolidated 

 nucleus, whereas spirochaetes do not. After this the view that 

 spirochaetes were bacteria was revived, particularly by Novy and 

 Knapp, on the following grounds : — ■ 



1. Absence of trophonucleus. 



2. Transverse division. 



3. Rapid multiplication. 



4. Absence of plasm olysis with distilled water. 



5. Persistence of form when acted upon by heat. 



6. The production of active immunity. 



7. The absence of aerotropism — i.e., the tendency to mass round 

 a bubble of air. 



. Dobell, as a result of his prolonged inquiries, ca' 3 to the con- 

 clusion that they are Schiophyta (bacteria + Cyanophyceae), and 

 not protozoa. He also concludes that they belong to the bacteria, 

 and probably constitute a group of the same systematic status as 

 the cocci, the bacilli, and the spirilla. 



On the other hand, there is a growing feeling among biologists that 

 spirochaetes are really protozoa — e.g., Dofiein, Minchin, Sambon, 

 Nuttall, Fantham, and Krzysztalowicz and Sisdlecki. Fantham 



