TREPONEMA PALLIDUM 149 



should always be on hand that the ulcers may be 

 wiped before examination and the hands disinfected 

 afterward. That sleeping with or using anything 

 belonging to a syphilitic must be avoided goes with- 

 out saying. 



Diagnosis. In the serum of a syphilitic, and the say- 

 ing goes, "once a syphilitic, always so," certain anti- 

 bodies are formed that can be made use of in diagnosis. 

 This is the basis of the Wassermann test upon the 

 blood. This is due to antibodies like bacteriolysins. 

 Its theory and practice are too intricately technical 

 to be included here. Suffice it to say that it is 

 certainly a positive test in 95 per cent, of syphilitic 

 cases. Otherwise syphilis is diagnosticated by finding 

 the treponema in the serum which exudes from chancres, 

 skin eruptions, and mucous patches, or the venereal 

 warts on mucous membranes. This serum is taken 

 and looked at unstained upon a background of India 

 ink or by what is called dark field illumination, which 

 is a process by which the light is made to shine upon 

 the body of the spiral from the side. It can also be 

 stained by appropriate methods, but its minute size 

 and paleness make this a trying test. 



Morphology and General Characteristics. The Spiro- 

 cli&ia pallida is a corkscrew-like, actively motile, 

 delicate thread. Its windings assume the form of a 

 large arc of a small circle, and vary from four to 

 twenty. It is yinnmr to y sir oo" mcn wide and from 

 -g-oVo- to TTOTF inch l n g- It moves by end flagella, 

 in a screwing and waving motion. It is killed rapidly 

 by drying, a very fortunate thing, as many people 

 are thereby protected. Against weak bichloride and 



