CHAPTER V. 49 



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 684. 



See also RETTERER, Journ. Anat. Phys., xxxiii, 1897, p. 463, and 

 xxxvii, 1901, p. 480. 



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

 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. I 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 684. 



MAXIMOW (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. Hie. 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. 273) takes 5 parts 5 per cent, sublimate, 15 

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



74. Sublamin (Ethylendiamin Sulphate of Mercury) is recommended 

 in 5 per cent, solution by KLINGMULLEB and VEIEL (Zeit. wiss. Mikr., 

 xxi, 1904, p. 58). 



75. Platinum Chloride. The substance used and intended by 

 the authors who have recommended this reagent is not the true 

 platinic chloride, or tetrachloride, PtCl 4 , but the compound H 2 PtCl 6 , 

 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 per 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, PtCl 2 , 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 I 

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



M. 4 



