TREPONEMA PALLIDUM 153 



tains motile organisms having the morphology of treponema pallidum, it is 

 strong, one might say conclusive, evidence of syphilis, as contamination is 

 practically precluded. 



EXAMINATION OF PAPULES 



The admixture of blood with material to be examined is avoided by pinching 

 up the papule with a hemostat, nicking the skin with a knife and obtaining the 

 serum with a capillary tube. 



Experience has shown there is great irregularity in the distribution of tre- 

 ponema in tissues, so that some sections of an organ will present few or no tre- 

 ponema while other sections of the same organ present many in each microscopic 

 field. 



The application of germicidal washes and dressings, especially those con- 

 taining mercury, to open syphilitic lesions, causes a disappearance of treponema 

 and attempts to firrd organisms in scrapings and fluid from such lesions are 

 usually futile until after such washings and dressings have been discontinued 

 for at least 12, better 24 hours. 



Subcutaneous and intracutaneous injections of cocain, and other methods 

 of producing local anesthesia, usually decreases the number of treponema that 

 may be found in syphilitic lesions or causes the treponema to totally disappear, 

 hence no attempt at producing local anesthesia should precede removal of fluid 

 or scrapings from ulcers, papules or lymphatic enlargements for examination 

 with the dark field microscope or microscopic examination after staining and 

 for the same reason no anesthetic should be applied prior to excision of tissue 

 to be examined for treponema. 



THE WASSERMANN TEST 



1. Under aseptic precautions at least 5 cc. of blood are obtained from a 

 prominent vein at the elbow with a sterile syringe; the blood is immediately 

 transferred to a sterile tube and placed in an ice box until serum separates from 

 the clot. 



2. The serum is collected and heated to 55C. for J^ hour in a water bath. 



3. The patient's serum is mixed with fresh guinea-pig serum and liver extract 

 and incubated at 37 for i hour. 



4. After incubating for an hour red blood corpuscles and serum of a rabbit, 

 immunized against them, is placed in the tube, which is again incubated for 

 an hour. 



If hemolysis occurs the reaction is negative (see page 241). 



