616 METHODS AND FORMULAS AMS 21.1 



light enters into the majority of metal staining reactions. The best that can be said of 

 these organic reducing agents, therefore, is that they will under certain empirically 

 estabhshed conditions reduce either to the metalUc form, or in most cases to metallic 

 oxides or proteinates, some unstable metallic complex which has formed on the surface 

 of the cell which it is desired to demonstrate. None of the more recent photographic 

 developing techniques appears to have been tried, and the majority of the formulas 

 given below appear entirely barbaric to a practical photographer. No formula has been 

 included in this section unless it is specifically recommended by the original author of 

 one of the metal stains given above. Most of the more successful metal stains are re- 

 duced with the aid of formaldehyde, and it remains yet to be demonstrated clearly 

 that any of these pseudophotographic developers are indeed an improvement over this 

 simple reagent. 



21 Developing Solutions 



21.1 foemulas 



21.1 Armuzzi and Stempel test. 1928 Schmorl Schmorl 1928, 406 



formula: water 100, gum arable 12, hydroquinone 0.25 



21.1 Ascoli 1911 3381,25:177 



formula: water 90, sodium sulfite, cryst. 10, amidol 0.5 



21.1 Balbuena 1922 21344,20:31 



formula: a. digest 30 oil of amber with 70 of 70% alcohol 1 week, separate; B. 1% 



hydroquinone 

 note: The original calls for Tinctura succini for solution A. This tincture is not in the 

 Spanish Pharmacopaeia, the formula given above being from the Portuguese {test. 

 Squire 1899 Companion to the Pharmacopaeia, p. 612). Langeron 1942, 627 uses 

 teinture alcoolique du succin {du Codex) which is prepared {test. Squire, loc. cit.) by 

 macerating 1 part powdered amber in 10 parts 80% alcohol. This would have a very 

 much lower oil content. 



21.1 Bauer 1944 608b, 29:297 



formula: water 100, gallic acid 1.43, tannic acid 0.86, sodium acetate 2.86 



21.1 Boccardi 1886 test. Lee 1905 Lee 1905, 252 



formula: water 80, formic acid 20, oxalic acid 0,3 



21.1 Bodian 1936 763,65:89 



formula: water 100, sodium sulfite 5, hydroquinone 1 



21.1 Boule 1908 15063, 10:15 



formula: water 100, 40% formaldehyde 6, 95% ale. 15, hydroquinone 1 



21.1 Cajal 1910a 21344, 8:3 



formula: water 250, 40% formaldehyde 15, pyrogallol 2.5 



21.1 Cajal 1910b 21344, 8:3 



formula: water 250, 40% formaldehyde 15, hydroquinone 2.5 



note: Cajal {loc. cit.) sometimes substituted 5 ml. pyridine, and sometimes 1.25 Gms. 

 sodium sulfite for the formaldehyde. 



21.1 Cajal 1914 21344, 12:127 



formula : water 100, hydroquinone 2, sodium sulfite, anhydr. 0.75, 40% formaldehyde 4 

 note: Cajal and de Castro 1933, 202, refer this formula, without reference, to Golgi 1908. 



21.1 Cajal 1921 21344, 19:71 



formula: water 70, 40% formaldehyde 30, hydroquinone 0.3 



21.1 Cajal 1925 21344,23:237 



formula: water 70, 40% formaldehyde 20, hydroquinone 0.3, acetone 15 



