422 



Syphilis 



another four or five seconds, after which it is shaken to and fro in the 

 water to wash it. It is next dried and examined at once or after mount- 

 ing in balsam. The spirochaetes appear violet in color. 



When serum from a primary sore or other syphilitic lesion 

 is treated by these methods, a number of spirochsetes appear 

 well stained and a number very palely stained, so that one 

 is in doubt whether there may not be many others unstained, 

 and this seems to be the case, for when similar smears are 

 treated by other methods many more can be found. 



The method of silver incrustation was first employed for 

 the demonstration of the organism in tissues, but Stern* 



Fig. 124. Treponema pallidum in the periosteum near an epiphysis 



(Bertarelli). 



has applied it with great success to the examination of 

 fluids by the following simple procedure: Spreads are made 

 in the usual manner, dried in the air, and then for a few 

 hours in an incubating oven at 37 C. They are next 

 placed in a 10 per cent, solution of nitrate of silver in a 

 colorless glass receptacle and allowed to rest in the diffused 

 daylight of a comfortably lighted room for a few hours, until 

 they become brownish metallic in appearance, when they 

 are thoroughly washed in water. The spirochaetes appear 

 black, the background brownish. 



* "Berliner klin. Wochenschrift," 1907, No. 14. 



