CHAPTER XVII. 201 



353. Other Salts of Silver. ALFEROW (Arch. Phys., i, 1874, p. 694) 

 employs the picrate, lactate, acetate, and citrate, in solution of 1 : 800, 

 and adds a small quantity of the acid of the salt taken (10 to 15 drops of 

 a concentrated solution of the acid to 800 c.c. of the solution of the salt). 

 This decomposes the precipitates formed by the action of the silver salt 

 on the chlorides, carbonates, and other substances existing in the tissues. 



REGAUD and DUBREUIL (C.R. Ass. Anat., 5 Sess. 1903, p. 122) take a 

 fresh solution of protargol or a mixture of equal parts of 1 per cent, 

 protargol and 1 per cent, osmic acid, thus avoiding precipitates. 



354. Silver Nitrate : Reduction. Reduction may be effected in 

 media other than distilled water. 



v. RECKLINGHAUSEN washed his preparations in salt solution 

 before exposing them to the light in distilled water (Arch. path. 

 Anat., xix, p. 451). Physiological salt solution (0-75 per cent.) is 

 commonly used for these washings. 



MULLER (Arch.f. path. Anat., xxxi, p. 110), after impregnation by 

 immersion for two or three minutes in a 1 per cent, solution of nitrate 

 of silver in the dark, adds to the solution a small quantity of 1 per 

 cent, solution of iodide of silver (dissolved by the aid of a little 

 iodide of potassium). After being agitated in this mixture the 

 preparations are washed with distilled water, and exposed to the 

 light for two days in a 1 per cent, solution of nitrate of silver (see also 

 GIERKE, in Zeit. wiss. Mik., i, 1884, p. 396). 



ROUGET (Arch, de PhysioL, 1873, p. 603) reduces in glycerin ; SztiTZ 

 (Zeit. wiss. Mik., xxix, 1912, p. 291) in glycerin with -^ of formol. 



SATTLER (Arch. mik. Anat., xxi, p. 672) exposes to the light for a 

 few minutes in water acidulated with acetic or formic acid. THAN- 

 HOFFER (Das Mikroskop, 1880) employs a 2 per cent, solution of 

 acetic acid. 



KRAUSS brings his preparations, after washing, into a light red 

 solution of permanganate of potash. Reduction takes place very 

 quickly, even in the dark. 



OPPITZ puts for two or three minutes into a 0-25 or 0-50 per cent, 

 solution of chloride of tin. 



JAKIMOVITCH (Journ. de I' Anat., xxiii, 1888, p. 142) brings nerve 

 preparations, as soon as they have become of a dark brown colour, 

 into a mixture of formic acid 1 part, amyl alcohol '1 part, and water 

 100 parts, and exposes to the light for five to seven days, the mixture 

 being renewed from time to time. 



DEKHUYZEN (op. tit., last ) reduces in oil of cloves, after dehydra- 

 tion. 



355. Fixation. LEGROS (Journ. de I' Anat., 1868, p. 275) washes his 

 preparations, after reduction, in hyposulphite of soda, to prevent after- 



