CHAPTER XXXIV. 475 



xlvii, 1901, p. 327) and is so quickly and easily carried out that 

 many sections can be manipulated at the same time. 



Processes similar to Golgi's Methods or suitable for the 



same Purposes. 



898. ZIEHEN'S Gold and Sublimate Method (N enrol. CentrbL, x, 

 1891, p. 65). Small pieces of fresh tissues are put into a large 

 quantity of a mixture of equal parts of 1 per cent, corrosive sublimate 

 and 1 per cent, gold chloride, and left therein for at least three weeks, 

 preferably for several months up to five, by which time they will 

 have become of a metallic red-brown colour. They are then gummed 

 to a cork or wooden cube and cut without embedding. Sections are 

 treated either with LUGOL'S solution diluted with 4 volumes of water, 

 or with diluted tincture of iodine, until duly differentiated, then 



*/ 



washed, dehydrated, and mounted in balsam. Both medullated 

 and non-medullated nerve-fibres, as well as nerve-cells and neuroglia 

 cells are stained. 



899. KROHNTHAL'S Lead Sulphide Impregnation (N enrol. CentrbL 

 xviii, 1889 ; Ztschr. iviss. Mikr., xvi, 1899, p. 235). Pure formic 

 acid is slowly added to a saturated solution of lead acetate till white 

 crystals of lead formiate are abundantly formed. The mother liquid 

 is filtered off, and the crystals are dissolved to saturation in distilled 

 water. Equal volumes of this saturated solution of lead formiate 

 and 10 per cent, formalin form the fixing fluid in which pieces of 

 brain or spinal cord are left for five days. Tissues are then directly 

 brought into a mixture of equal parts of 10 per cent, formalin and 

 sulphuretted hydrogen. After a few minutes the first discoloured 

 portion of this mixture is poured off and replaced with fresh solution, 

 in which pieces remain for another five days. They are then 

 gradually dehydrated and embedded in celloidin. Sections are 

 cleared in carbol-xylol (1:1) and mounted in balsam under a cover. 

 Nerve-cells and nerve-fibres are extensively impregnated. 



CORNING (Anat. Anz., xvii, 1900, p. 108) hardens the tissues in 

 10 per cent, formalin and then brings them into the lead formiate, 

 w T hich he buys from Merk. He prefers to cut without embedding. 



900. WOLTER'S Chloride of Vanadium Process (Ztschr. iviss. Mikr., 

 vii, 1891, p. 471). Central or peripheral nervous tissues are fixed 

 in Kultschitzky's solution, followed by alcohol as described in 55. 

 Celloidin sections, 5 to 10 //, thick, are mordanted for twenty-four 

 hours in a mixture of 2 parts of 10 per cent, vanadium chloride and 

 8 parts of 8 per cent, aluminium acetate. They are then washed 



