734 



THE SPIROCILETE OF SYPHILIS 



difficult part of the experiment is to differentiate the Treponema pallidum 

 from the various similar spirochsetes which are not infrequently present in 

 these preparations (fig. 349). A certain amount of experience is necessary 

 before it is possible to be certain of the diagnosis. 



III. Examination of stained preparations. With regard to the staining of 

 films and sections for the detection of the treponema, Borel and Burnett's 

 method is rapid and is particularly recommended. Giemsa's method is also 

 good. For sections, the silver impregnation method is undoubtedly the 

 best. 



3. Identification of the organism. 



The Treponema pallidum is differentiated from all other spirochsetes by 

 several characteristics. 



1. It has an average length of 10-15/x but is often longer and is extremely 

 slender, measuring on an average 0'25/A transversely. 



2. Its index of refraction is very low 

 indeed in fresh preparations, so that with 

 an ordinary microscope it is only visible 

 with a very good apochromatic objective. 

 On the other hand, it is readily visible 

 by dark-ground illumination. 



3. It has no undulatory membrane. 



4. Its pointed ends terminate in a long 

 ciliary filament. 



5. It is circular in transverse section. 



6. It is in form a complete spiral like 

 a corkscrew. This characteristic spiral 

 arrangement is seen both when the or- 

 ganism is in motion and when at rest. 



7. The turns of the spiral are deep, 



close an , d ^- The "Banian pomms 

 a considerable degree of elasticity so that 

 it is not easy to deform it. 



8. In vitro its vitality is low so that when watched under the ultra-micro- 

 scope the movements cease in 5-6 hours at the temperature of the laboratory. 



9. The treponema stains with difficulty and is coloured red with Giemsa's 

 solution. 



Spirochsetes closely resembling the Treponema pallidum. 



The following are the principal spirochsetes with which the Treponema 

 pallidum is likely to be confused : 



A. Spirochaeta refringens. This spirochaete occurs in smegma, and in 

 ulcerating lesions of the skin. It is sometimes found associated with the 

 Treponema pallidum in ulcerating syphilitic lesions, but in these cases it 

 occurs near the surface and not deep in the tissues. 



The Spirochceta refringens is larger and longer than the Treponema pallidum 

 and in the fresh condition is highly refractile. The turns of the spiral are 

 fewer in number and of greater amplitude, less regular and flattened. The 

 periplast often simulates an undulatory membrane. There is only one 

 flagellum and this is attached laterally to one of the rounded ends (Levaditi). 

 The movements are much more rapid than those of the Treponema pallidum 

 and it is often impossible to follow them under the microscope. It stains 

 easily with the ordinary dyes and stains blue with Giemsa's solution. 



B. Spirochaeta balanitidis. Hofmann and Prowazek described this 

 organism as being present in a case of circinate ulcerative balanitis. It 



Htic papiiioma. x 1500. 



