550 METHODS AND FORMULAS MS 31.1 



changes of triple-distilled water. It is es- microscope, that the gum mastic has been 



sential at this stage to remove the whole removed. If many slides are being treated 



of the silver nitrate from the gum mastic in one coplin jar, it is usually better to 



complex which covers the sections. treat them for about five minutes in a 



After the sections have been ade- first bath of alcohol and then to pass them 



quately washed, they are placed in the to a second, clean alcohol bath for at least 



milky developing solution for from 5 to 15 ten minutes. A very simple test is to lift 



minutes, or until they become dark brown, the slide from the alcohol and to permit it 



They should not turn completely black, to drip into some convenient vessel of dis- 



and it is much better to develop them too tilled water. If the least cloudiness is 



little than too much. After removal from observed, the slide must be placed in clean 



the developing solution, they are thor- alcohol and re-treated. Tliis must be re- 



oughly washed in several changes of peated until such time as the drops of 



triple-distilled water. This is essential, be- alcohol falling from the surface fail to go 



cause the developing solution itself will cloudy in distilled water. The sections are 



tend to darken by oxidation, and, if left in then treated in acetone (to remove any 



the tissue, will itself become so dark that alcohol-insoluble fraction of the gum 



it will mask the spirochetes. The sections mastic which may remain), cleared in 



are then placed in 95% alcohol, in which xylene, and mounted in balsam. Success- 



they are left until it is apparent, on ex- ful preparations show spirochetes in black 



amination under a low power on the against a gray background. 



31.1 Staining Solutions 



In all these solutions the silver nitrate is first dissolved in water. The other ingredients are 

 then mixed and added to the silver solution. 



31.1 Balbuena 1922 21344,20:31 



FORMULA : water 100, silver nitrate 0.05, pyridine 1 



31.1 Bauer 1944 608b, 20:297 



formula: water 50, 95% ale. 50, acetic acid 0.2, silver nitrate 1.5 



31.1 Cajal 1910 21344, 8:5 



formula: water 72, silver nitrate 1.4, 95% ale. 28 



31.1 Cajal 1921 21344,19:71 



formula: water 100, silver nitrate 2, pyridine 2 



31.1 Cajall925 21344,23:23 



formula: water 60, silver nitrate 1.2, pyridine 2, 90% ale. 30 



31.1 Cajal 1925 (est. 1933 /p.s. Cajal and de Castro 1933, 262 



formula: water 100, silver nitrate 2, pyridine 3, 40% formaldehyde 5 



31.1 Cajal 1929 21344, 26:1 



FORMULA : water 100, silver nitrate 2, pyridine 0.3 



31.1 Davenport 1930 1879, 24:690 



formula: water 10, silver nitrate 10, 90% ale. 90, nitric acid 0.4 



31.1 Lauda and Rezek 1928 22575, 269:218 



formula: dissolve with heat 0.1 gelatin in 100 water. Cool. Add 3 silver nitrate. 



31.1 Levaditi test. 1916 Warthin 4349, 6:56 



formula : water 90, pyridine 10, silver nitrate 0.9 



31.1 McManns 1943 11431,65:503 



formula: water 100, silver nitrate 20, chloral hydrate 1 



31.1 Podhradszky 1934 23632, 50 :285 



formula: water 10, 95% ale. 90, silver nitrate 10, nitric acid 0.3 



