596 PATHOGENIC MICROORGANISMS 



strated by Bandi and Simonelli* who found them in the blood taken 

 from the roseola spots, and by Levaditi and Petresco ^ who found them 

 in the fluid of bhsters produced upon the skin. 



In tertiary lesions the spirochsetes have been found less regularly 

 than in the primary and secondary lesions, but positive evidence of their 

 presence has been brought by Tomasczewski,^ Ewing,^ and others who 

 succeeded in demonstrating them in gununata. Noguchi and Moore ^ 

 have recently found the Spirochseta palUda in the brain of patients dead 

 of general paresis. 



In congenital syphiHs, many observers have found Spirochaeta 

 pallida in the lungs, liver, spleen, pancreas, and kidneys, and, in isolated 

 cases, in the heart muscle. The organisms were always present in large 

 numbers and practically in pure culture. These results more than any 

 others seem to furnish positive proof of the etiological relationship be- 

 tween the spirochsete and the disease. 



Demonstration of Spirochaeta pallida.^ — In the living state the 

 spirochsetes have been observed in the hanging drop or under a cover- 

 slip rimmed with vaseline. It is extremely important, in preparing such 

 specimens from primary lesions or from lymph glands, to obtain the 

 material from the deeper tissues, and thus as uncontaminated as possible 

 by the secondary infecting agents present upon the surface of an ulcer, 

 and also as free from blood as possible. An ordinary microscope 

 and condenser may be used, provided that the light is cut down con- 

 siderably by means of the iris diaphragm. This method is, however, 

 difficult and uncertain. It is better to employ a special device known 

 as a "condenser for dark-field illimiination" (Dunkel-Kammer- 

 Beleuchtung). This apparatus is screwed into the place of the Abbe 

 condenser. The preparation is made upon a slide and covered with a 

 cover-slip as usual. A drop of oil is then placed upon the upper sur- 

 face of the dark chamber and the slide laid upon it so that an even 

 layer of oil, without air-bubbles, intervenes between the top of the dark 

 chamber and the bottom of the slide. The preparation is then best 

 examined with a high-power dry lens. An arc light furnishes the most 

 favorable illumination. In such preparations the highly refractive cell- 



1 Bandi und SimonelU, Cent. f. Bakt., 40, 1905. 

 'Levaditi et Petresco, Presse med., 1905. 



2 Tomasczewski, Munch, med. Woch., 1906. 

 ^Ewing, Proc. N. Y. Path. Soc, N. S., 5, 1905. 



^ Nogiichi and Moore, Jour. Exp. Med., xvii, 1913, 



