450 MYELIN STAINS. 



WEIGERT (Ergebn. Anat., vii, 1897 (1898), pp. 1 8) ; MATUSZEWSKI 

 (Arch. path. Anat., clxxix, 1905, p. 12) ; DE LANGE (Le Nevraxe, 

 x, 1908, p. 83) ; and LEWY (Fol. Neurobiol, ii, 1909, p. 471). 



FINOTTI (Virchow's Arch., cxliii, 1896, p. 133) makes sections of 

 material that has been in Miiller's fluid for not more than a few 

 weeks or months, and puts them for four to ten hours (in the dark) 

 into a freshly prepared mixture of 1 or 2 parts of 1 per cent, osmic 

 acid, and 1 part of a concentrated solution of picric acid in one-third 

 alcohol. For peripheral nerves ; myelin (normal), black. 



ORR (Journ. Path, and Bad., vi, 1900, p. 387) treats small pieces 

 of fresh tissue with a mixture of 8 c.c. of 2 per cent, osmic acid, and 

 2 c.c. of 1 per cent, acetic acid, which increases the penetration. 

 Should the mixture be darkened at the end of twenty-four hours, 

 then it ought to be renewed. After forty-eight hours, the pieces are 

 placed in 10 per cent, formalin for three days to complete reduction 

 and hardening. 



VASSALE (Arch. Ital. BioL, xxvii, 1897, p. 131) takes 75 c.c. of 

 Miiller's solution, 25 c.c. of 1 per cent, osmic acid, and 20 drops of 

 nitric acid. 



NISSL (Encyd. mik. Technik., ii, p. 248), holding that alcohol 

 attacks the myelin, cuts without imbedding, and hurries sections 

 through alcohol and bergamot oil into balsam. 



RAMON T CAJAL (Trdb. lab. Bid. Madrid, ii, 1903, p. 93) has a com- 

 plicated method of treating March! material. 



BUSCH (N enrol. Centralb., xvii, 1898, p. 476) puts formal material 

 for five to seven days into a solution of 1 part osmic acid, 3 of iodate 

 of sodium, and 300 of water. Same stain as Marchi's, but more 

 penetrating and sharper. 



See also VENDEROVIC (Anat. Anz., xxxix, 1911, p. 414) who cuts 

 slices of formol material -5 cm. thick, and treats these, with Marchi's 

 fluid, thus getting increased depth of reaction. 



STEENSLAND (Anat. Rec., viii, 1914, p. 123) recommends clearing 

 sections of Marchi material with oleum origani cretici, and mounting 

 in chloroform-balsam. 



Osmic Acid (EXNER, Sitsb. Akad. Wiss. Wien, Ixxxiii, 1881, Abth. 3, 

 p. 151 ; BEVAN LEWIS, The Human Brain, 1882, p. 105). A portion 

 of brain, not exceeding a cubic centimetre in size, is placed in 1 per cent, 

 osmic acid, and after five to ten days is cut (best without imbedding). 

 The sections are treated with caustic ammonia (20 drops to 50 c.c. of 

 water), which clears up the general mass of the brain substance, leaving 

 the medullated fibres black. The preparations are not permanent, unless 

 (RANVIER, Traite, 1 ed., p. 1086) they are fixed for a quarter of an 

 hour in osmic acid vapour. 



