424 Syphilis 



distilled water, 100 c.c., and kept in the dark, at room tem- 

 perature, from twenty-four to seventy- two hours, then 

 washed in distilled water, embedded in paraffin, and cut. 

 The spirochaetes are intensely black, the tissue yellow-brown. 

 The sections are finally stained with (a) Giemsa's st#in for 

 a few minutes, then washed in water, differentiated with 

 absolute alcohol containing a few drops of oil of cloves, 

 cleared with oil of bergamot or xylol, or (b) concentrated 

 solution of toluidin blue, differentiated in alcohol containing 

 a few drops of Unna's glycerin-ether mixture, cleared in oil 

 of bergamot, then in xylol, and mounted in Canada balsam. 



This method was later improved by Levaditi and Manou- 

 elian* by the addition of 10 per cent, of pyridine to the 

 silver bath just before the block of tissue is put in, and 

 by using for the reducing bath a mixture of pyrogallic 

 acid, acetone, and pyridin. The details are as follows: 

 Fragments of organs or tissues 1-2 mm. in thickness are 

 fixed for twenty-four to forty-eight hours in a solution of 

 formalin 10 : 100, then washed in 96 per cent, alcohol for 

 twelve to sixteen hours, then in distilled water until the 

 blocks fall to the bottom of the container. They are 

 then impregnated by immersion in a bath composed of 

 a i per cent, solution of nitrate of silver to which, at the 

 moment of employment, 10 per cent, of pyridin is added. 

 Keep the blocks immersed in this solution at room tem- 

 perature for two or three hours, and at 50 C. for four or 

 six hours, then wash rapidly in a 10 per cent, solution of 

 pyridin, and reduce in a bath composed of 4 per cent, pyro- 

 gallic acid, to which, at the moment of using, 10 per cent, of 

 pure acetone and 15 per cent, (total volume) of pyridin are 

 added. The reduction bath must be continued for several 

 hours, after which the tissue goes through 70 per cent, 

 alcohol, xylol, paraffin, and sections are cut. The sections, 

 fastened to the slide, are stained with Unna's blue or tolu- 

 idin blue, differentiated with glycerin -ether, and finally 

 mounted in Canada balsam. 



Distribution. The organisms are not known in nature 

 apart from the lesions of syphilis. They have now been 

 found in all the lesions of this disease and in the blood of 

 syphilitics in larger or smaller numbers. This discovery has 

 greatly modified our ideas of the tertiary stage, for the 

 demonstration of the organisms in its lesions shows them to 



* "Compt. rendu de la Soc. de Biol. de Paris," 1906, LVIII, p. 134. 



