612 A MANUAL OF BACTERIOLOGY 



CLINICAL EXAMINATION FOR SYPHILIS 



A. EXAMINATION FOR THE S. PALLIDUM. 



1. Examination by dark-ground illumination. The sore should 

 be carefully cleaned with a piece of wool moistened with saline 

 or tap-water. The sore is then firmly squeezed until drops of 

 serum exude. If this fails, the sore may be lightly scraped with 

 a blunt-edged scarifier and squeezed. If bleeding occurs, it is 

 necessary to wait until it ceases. The serum is collected in a 

 capillary pipette. The clear serum is then examined by dark- 

 ground illumination as soon as possible. If fresh, the Spironema 

 will be motile. 



2. Indian-ink method. A drop of serum obtained as in (1) is 

 mixed with a drop of Indian ink on a slide and spread in a thin 

 film. The film is air-dried and examined with the oil-immersion 

 lens. The Spironema appears as a delicate white undulating thread 

 on a dark ( yellowish to dark brown) background (Plate XXV, b). 

 The ink may be either the fluid, provided it is not too old, or may be 

 prepared with the stick form. Benian's congo-red method (p. 123) 

 may be similarly employed. Care must be taken not to mistake 

 other spirochaetes, e.g., S. refringens, for the Spironema. 



If the number of turns of the spiral of the syphilitic spiro- 

 chaete be counted, six or seven turns will be found in a length 

 equal to the diameter of a red blood-cell. The distance from 

 the top of one spiral to the next is from 1 to 1-2 p.. As red 

 blood-cells measure about 7-5/x in diameter, on an average six 

 or seven turns will be equal to the diameter of a red blood -cell. 

 The Spironema varies in length from 6 to 15 p., or even more, 

 and consequently contains from six to fourteen and sometimes 

 twenty or more turns. This measurement of the length of the 

 spiral is usually possible, and is of the greatest value in identifying 

 the Spironema. 



3. Stained preparations. Smears from chancres, etc., may be 

 stained by the Giemsa method. 



The smears are fixed for ten minutes in absolute alcohol. The 

 preparations are then stained in a dilute solution of the Giemsa 

 solution for two to twenty-four hours, washed in distilled water, 

 dried, and mounted. (The dilute Giemsa is prepared by adding 

 one drop of the Giemsa stain to a cubic centimetre of "best " 

 distilled water, and rendering alkaline with one drop of 0-01 per 



