408 MICROBIOLOGY 



Schaudinn 's discovery that the cause of syphilis is an organism 

 belonging to the Treponema (Spirochaeta) pallidum revived 

 interest in this group of organisms. Novy and Knapp * con- 

 cluded that the spirochaeta are bacteria. The best known, 

 morphologically, of these forms is the type genus spirochaeta 

 with undulating membrane and without flagella. According 

 to Calkins, 2 there are two genera of these organisms, namely, 

 Spirochaeta and Treponema. To the spirochaeta belong Sp. 

 plicatilis of Ehrenberg and Sp. balbianii found by Cretes in 

 oysters and clams and a number of forms referred to this 

 genus but which are not fully described. A number of these 

 have been found in the blood of horses, sheep and other ani- 

 mals, in tumors, pustules and on normal mucous membranes. 

 Spirochaeta Obermeieri of relapsing fever in man belongs to 

 this genus. 



The spirochaetes are largely spiral in form and some of 

 them have transverse bands of chromatin. The nuclear appa- 

 ratus is of the "diffuse" type which represents an intermedi- 

 ate condition between the "distributed nucleus" of bacteria 

 and the morphological nucleus of higher cells. The flagella of 

 the genus treponema may be the attenuated ends which remain 

 after the longitudinal division. The spirochaetes seem to divide 

 longitudinally. Many of these organisms seem to be intra- 

 cellular parasites, others live in the lymph and blood and others 

 .are neither parasitic nor commensal in their mode of life. 

 Treponema gallinarum is said to frequently leave the blood 

 plasma and to penetrate the blood corpuscles of the chick. T. 

 Duttoni penetrates the egg of the tick. These organisms are 

 often transmitted by insects. Nuttall showed experimentally 

 that bed bugs transmit Sp. recurrentis from man to man, T. 

 Duttoni is conveyed by' a tick (Ornithodorus manbata) , 

 'Treponema gallinarum is transmitted by a tick (Argas mini- 

 atis) and T. Theileri by Rhipicephalus decoloratus. It has also 

 been shown that multiplication of the parasites occurs in the 



*Novy and Knapp. Jour, of Infect. Diseases, Vol. Ill (1906) 

 p. 291. 



1 Calkins. Zoo. cit. 



