Staining 721 



Burri* has recommended a simple and rapid method of demon- 

 strating the treponema and other similar organisms by the use of 

 India ink. 



A drop of juice is squeezed from a chancre or mucous patch and mixed with a 

 drop of India ink and then spread upon a glass slide as in making a spread of a 

 drop of blood. As the ink dries it leaves a black or dark brown field upon which 

 the spiral organisms stand out as shining, colorless, and hence conspicuous 

 objects. Williams uses Higgins' water-proof ink, and Hiss recommends "chin- 

 chin, Giinther- Wagner liquid pearl ink, for the purpose. 



The method is fairly satisfactory for diagnosis and can be applied 

 in a few moments. 



Fig. 296. Treponema pallidum impregnated with silver. Film prepared from 

 the skin of a macerated, congenitally syphilitic fetus. X 750 diameters (Flex- 

 ner). The dense aggregation of organisms may indicate agglutination. 



II. Section. Staining the organism in the tissues is a more 

 difficult matter, for the Giemsa stain scarcely shows it at all. Bert- 

 arelli and Volpinof tried a modification of the van Ermengen method 

 for flagella with some success, but there was no real success until 

 LevaditiJ devised his methods of silver impregnation. 



This consists in hardening pieces of tissue about i mm. in thickness in 10 per 

 cent, formol for twenty-four hours, rinsing in water, and immersing in 95 per cent, 

 alcohol for twenty-four hours. The block is then placed in diluted water until 

 it sinks to the bottom of the container, and then transferred to a 1.5 to 3 per cent, 

 aqueous solution of nitrate of silver in a blue or amber bottle and kept in a dark 



* "Wiener klin. Wochenschrift," July i, 1909. 

 t "Centralbl. f. Bakt. u. Parasitenk.," Orig., 1905, XL, p. 56. 

 J " Compt.-rendu de la Soc. de Biol. de Paris," 1905, LIX, p. 326. 

 46 



