DISEASES CAUSED BY SPIROCILETES 861 



its infancy and that we know very little about the systemic reactions 

 which follow infection with the Spirochaeta pallida. 



The fact that the syphilitic virus does not pass through a filter 

 has been demonstrated by Klingmiiller and Baermann, 37 who in- 

 oculated themselves with filtrates from syphilitic material. 



Hopkins and the writer have carried out some seventy filtration 

 experiments with culture treponemata at various stages of growth 

 without ever obtaining filter passage. It is our opinion that the 

 assumption of a filtrable stage of the syphilitic virus is entirely un- 

 justified and devoid of valid experimental support. 



THE SPIRQCHJETES OF RELAPSING FEVER 



The microorganisms causing relapsing fever were first observed 

 in 1873, by Obermeier, 38 who demonstrated them in the blood of 

 patients suffering from this distinct type- of fever. Since his time 

 extensive studies by many other observers have proven beyond 

 question the etiological connection between the disease and the 

 organisms. 



Morphology and Staining. The spirochaste of Obermeier is a 

 delicate spiral thread measuring from 7 to 9 micra in length (Novy), 

 and about 1 micron in thickness. While this is 'its average size, it 

 may, according to some observers, be considerably longer than this, 

 its undulations varying from four to ten or more in number. Com- 

 pared with the red blood cells among which they are seen, the 

 microorganisms may vary from one-half to nine or ten times the 

 diameter of a corpuscle. In fresh preparations of the blood, very 

 active corkscrew-like motility and definite lateral oscillation are 

 observed. In stained preparations no definite cellular structure can 

 be made out, the cell body appearing homogeneous, except in de- 

 generated individuals, in which irregular granulation or beading 

 has been observed. Flagella have been described by various ob- 

 servers. Novy and Knapp 39 believe that the organisms possess only 

 one terminal flagellum. Zettnow, 40 on the other hand, claims to 

 have demonstrated lateral flagella by special methods of staining. 



37 Klingmuller und Baermann, Dent. med. Woch., 1904. 



38 Obermeier, Cent. f. d. med. Wiss., 11, 1873. 



39 Novy and Knapp, Jour, of Infec. Dis., 3, 1906. 

 "Zettnow, Deut. med. Woch., 32, 1906. 



