CHLORIDES ORGANIC ACIDS ETC. 47 



these see §§ 50, 51, 54, as well as the mixtures given under "Picric 

 Acid " and " Formol." 



81. Rabl {Zeit. wiss. Mikr., xi, 1894, p. 165) takes for embryos of 

 vertebrates, and also for other objects, 1 vol. of 1 per cent, platinum 

 chloride, 1 of saturated sublimate, and 2 of water. 



Lenhossek {Arch. mikr. Anat., li, 1898, p. 220) takes 20 parts of 

 1 per cent, platinum chloride, 20 of 5 per cent, sublimate, and 1 of 

 acetic acid. 



82. Palladium Chloride (Sciiulze, Arch. mik. Anat., iii, 1867, p. 477). 

 Used by Schulze as a hardening agent in a 1 : 800 solution, acidified 

 with hydrochloric acid. 



Cattaneo has used it in solutions of 1 : 300, 1 : 600, or 1 : 800 

 strength, for from one to two minutes, for Infusoria. 



Frenkel (Anat. Anz., viii, 1893, p. 538) recommends for connective 

 tissue a mixture of 15 parts 1 per cent, palladium chloride, 5 parts 2 per 

 cent, osmic acid, and a few drops of acetic acid. 



83. Iridium Chloride (Eisen, Zeit. zviss. Mik., xiv, 1897, p. 195). 

 Solution of I or I per cent., acidified with 1 per cent, of glacial acetic 

 acid. 



^Vith the ovotestis of the snail, Lee has obtained about the worst 

 fixation he has ever seen, but with the testis of Triton much better 

 results. 



84. Osmium Chloride (Eisen, Journ. of Morph., xvii, 1900). Solution 

 of ^ to j\f per cent. From specimens we have seen we should say it is 

 useless. 



85. Perchloride of Iron (Fol, Zeit. wiss. ZooL, xxxviii, 1883, p. 491, 

 and Lehrb. d. vcrgl. mik. Anat., p. 102). Fol recommends 1 vol. of 

 Tinct. Ferri Perchlor. B.P. diluted with 5 to 10 vols, of 70 per cent, 

 alcohol. 



The tincture diluted with 3 to 4 vols, of either alcohol or water has 

 been recommended for fixing medullated nerve by Platner {Zeit. wiss. 

 MiVv., vi, 1889, p. 187). 



86. Iron Alum. Strong {Journ. Camp. Neur., xiii, 1903, p. 296) fixes 

 (and decalcifies) heads of young Acanthi as in 9 parts of 5 per cent, 

 solution of iron alum with 1 of formol, for about two weeks. 



87. Chloride of Zinc is sometimes used for hardening brain (see 

 Part II). GiLSON {La Cellule, vi, 1890, p. 122) has used it as a fixative 

 for the silk glands of Lepidoptera, as follows : 



Glacial acetic acid .... 5 c.c. 



Nitric acid (80 per cent, nearly) . . 5 ,, 



Alcohol of 80 per cent. .... 100 „ 

 Distilled water ..... 300 ,, 

 Dry chloride of zinc . . . .20 grm. 



88. Iodine. Kent {Manual of the Infusoria, 1881, p. 114) uses 

 it for fixing Infusoria. Prepare a saturated solution of potassivun 

 iodide in distilled water, saturate this solution with iodine, filter, 

 and dilute to a brown-sherry colour. A very small portion ojily 

 of the fluid is to be added to that containing the Infusoria. 



Or you may use Lugol's solution : 



Water ...... 100 parts. 



Iodide of potassium . . . . 6 ,, 



Iodine . . . . . . 4 ,, 



Or for small marine animals, a solution of iodine in sea -water. 



Personally we have found it very useful for the examination of 

 spermatozoa. See also under Goodrich's lodine-Bouin method. 



