SPIROCH^TE PALLIDA 517 



easily decolorised by acids than the tubercle bacillus. The 

 etiological relationship of the organism to the disease was, 

 however, not generally accepted, and in view of the recent work 

 on syphilis, the organism cannot be regarded as having any 

 pathological importance. 



Spirochsete pallida. An entirely new light was thrown on 

 the etiology of the disease by the work of Schaudinn and 

 Hoffmann which appeared in 1905, and since that time their 

 conclusions have been completely confirmed. These observers 

 found in cases of syphilis an organism to which they gave the 

 name spirochcete pallida it now also goes by the name spironema 



FIGS. 156 and 157. Film preparations from juice of hard chancre 

 showing spirochaete pallida. Giemsa's stain. xlOOO. (From pre- 

 parations by Dr. A. MacLennan. ) 



or treponema pallidum. It is a minute spiral-shaped organism, 

 showing usually from six to eight curves, though longer forms 

 are met with ; the curves are small, comparatively sharp, and 

 regular (Figs. 156, 157). It may be said to measure 4 to 14 /t in 

 length, while it is extremely thin, its thickness being only '25 //,. 

 In a fresh specimen, say a scraping from a chancre suspended 

 in a little salt solution, the organism shows active movements, 

 which are of three kinds rotation about the long axis, gliding 

 movements to and fro, and movements of flexion of the whole 

 body. The ends are pointed and tapering. Its detection is 

 comparatively difficult, as the organism is feebly refractile, and 

 more difficult to see than most other organisms ; the movement 

 of small particles in the vicinity, however, is of assistance in 

 finding it. The use of the parabolic sub-stage condenser (p. 93) 

 is of great service in searching for the organism. 



In ulcerated syphilitic lesions other organisms are, of course, 

 present, and not infrequently another spiral organism, to which 



