46 FIXING AND HARDENING AGENTS 



78. Sublimate and Bichromate. Zenker's Mixture {Milnchener 

 med. Wochensckr., xxiv., 1894, p. 534 ; quoted from Mercier, 

 Zeit. zviss. Mik., xi, 4, 1894, p. 471). Five per cent, of sublimate 

 and 5 per cent, of glacial acetic acid dissolved in solution of 

 Muller. Fix for several hours or overnight, wash out with water, 

 treat the tissues in bulk, or the sections with alcohol containing 

 tincture of iodine. Refer to § 68. 



See also Retterer, Jour. Anat. Phys., xxxiii, 1897, p. 463, and 

 xxxvii, 1901, p. 480. 



If the objects are allowed to remain too long in the fluid there may he 

 formed precipitates, which it is very difficult to remove. Spuler 

 {Encycl. mik. Technik., 1st ed., p. 1280) says that they may be 

 avoided by removing the objects as soon as penetrated, and com- 

 pleting the hardening in liquid of Muller. We recommend this 

 method. 



Helly {Zeit. wiss. Mik., xx, 1904, p. 413) omits the acetic acid 

 and adds, immediately before use, 5 per cent, of formol. This is 

 a splendid fixative for vertebrate material. Fix overnight, wash 

 out in running water for several hours. See footnote to § 698. 



Maxlmow {ib., xxvi, 1909, p. 179) adds 10 per cent, of formol 

 and sometimes 10 per cent, of osmic acid of 2 per cent, (fix in the 

 dark). 



FoA (Quart. Journ. Mic. Sci., 1895, p. 287) takes equal parts of 

 saturated solution of sublimate in normal salt solution, and of liquid of 

 Miiller, or 5 per cent, solution of bichromate. 



HoYER (Arch. mikr. Anat., liv, 1899, p. 97) takes 1 part 5 per cent, 

 sublimate and 2 of 3 per cent, bichromate. 



KoHN {ib., Ixx, 1907, p. 278) takes 5 parts 5 per cent, sublimate, 15 

 parts 3J per cent, bichromate, and 1 part acetic acid. 



79. Sublamin (Ethylendiamin Sulphate of Mercury) is recommended 

 in 5 per cent, solution by Klingmijller and Veiel {Zeit. wiss. Mikr., 

 xxi, 1904, p. 58). 



80. Platinum Chloride. The substance used and intended by the 

 authors who have recommended this reagent is not the true platinic 

 chloride, or tetrachloride, PtCl4, but the compound HaPtClg, that is, 

 platinochloric, or hydro-chloro-platinic acid, by custom called platinum 

 chloride. It occurs as brown-red crystals, easily soluble in water and 

 very deliquescent. For this reason it had better be stocked in the form 

 of a 10 jjer cent, solution, kept in the dark (weak solutions — 0-5 per 

 cent. — may be kept in the light). 



It appears that some authors have stated that they were using 

 platinous chloride, PtClg, but that is not possible, as this salt is not 

 soluble in water. 



Rabl {Morph. Jahrb., x, 1884, p. 216) employed an aqueous solution 

 of 1 : 300. The objects remained in it for twenty-four hours, and 

 were then washed out with water. Well-washed preparations give 

 good chromatin stains with the " basic " tar colours ; but we find, as 

 do others, that plasma-staining with the " acid " colours is rendered 

 extremely difficult. It causes a certain shrinkage of chromatin. 



It is now almost always employed in the form of mixtures. For 



