CHAPTER XLII 



TREPONEMA PALLIDUM 



Treponema pallidum is present in the ulcers and skin lesions of syphilis, most 

 numerous in the primary and secondary period of the disease, scant later in the 

 infection. In small numbers they are present in the blood at times during 

 the disease and present in the enlarged glands and affected organs. 



Morphology. Treponema pallidum is variable in length, averaging about 

 '6 fj, long and 0.25 /* in diameter. It is spiral, showing from five to twenty curves, 

 which are fairly uniform in depth and length; they are deepest at the center and 



gradually become less marked toward the 

 ends, just like a corkscrew. The ends are 

 pointed and there is said to be a single term- 

 inal flagellum. Treponema pallidum is 

 actively motile and progresses with a screw- 

 like motion; lateral motion is less marked. 

 Reproduction occurs by both longitudinal 

 and transverse division. 



Staining. Ordinary .bacterial stains fail 

 to or only poorly stain treponema pallidum. 

 The best method of staining smears is the 

 following: 



PALLIDUM. 



FIG. , 29. TREPONEMA 

 (Coplin.) 



Left half, Giemsa stain, spread 

 from congenital syphilis; right half, 

 Levaditi stain of section of lung, 

 congenital syphilis; this (silver 

 method) makes the organisms appear 

 much broader. A, Pairs united at 

 one end. B, Twisted pairs. C, 

 Double length, apparently dividing 

 form. 



GIEMSA'S METHOD 



1. Make a thin, even smear, dry in air 

 without heating. 



2. Fix in absolute alcohol for J^ hour. 



3. Apply the following stain for i hour: 

 Giemsa's solution (Griibler), i part. 



1 per cent, aqueous sol. sodium carbonate, i part. 

 Distilled water, i part. 



After staining, wash with distilled water, dry in air and mount. 



The stain must be freshly prepared just before using. 



For the staining of treponema in tissue the following is most satisfactory: 



LEVADITI'S METHOD 



1. Cut the fresh tissue into small, thin pieces. 



2. Fix in 10 per cent, formalin for 24 hours. 



3. Harden in absolute alcohol for 24 hours. 



4. Wash in distilled water. 



5. Place in following solution, freshly prepared: 



2 per cent, aqueous solution of silver nitrate, 90 cc. 



150 



