84 THE AMEKICAN MOKTHLY [May, 



Notices of New Methods. — III. 



By GEORGE C. FREEBORN, M. D., 



INSTRUCTOR IN NORMAL HISTOLOGY, COLLEGE OF PHYSICIANS AND SURGEONS, NEW YORK CITY. 



Sublimate as a Hardening Medium for the Brain.* A. Diomidoff. 

 — Pieces of fresh brain, i c.c. in size, are placed in a 7% aqueous solution of 

 mercuric chloride for five to nine days, then successively in ^o^j^, 70%, and 

 96% alcohol. The pieces must remain in each alcohol for twenty-four hours. 

 Tissues hardened by this method are easily cut and are readily stained with 

 any of the aniline dyes, but unfortunately they cannot be stained by Weigert's 

 haematoxjdin method. 



This method, according to the author, is especially valuable for experi- 

 mental pathological work. Coagulation necrosis of the nerve elements, 

 changes in the nuclei in traumatic inflammation, pigment granules, as well 

 as cell alterations in progressive paralysis, dementia senilis, etc., are shown 

 well. 



New Methods of Preparing Nerve Cells. L. V. Thanhofterf. — i. A 

 bit of the fresh gray substance is placed between two cover-glasses, these are 

 pressed together, forcing the bit of tissue out into a thin layer. The cover- 

 glasses are then sHd apart and heated over the flame of an alcohol lamp or 

 Bunsen burner vmtil the thin sheet of tissue becomes of a blackish-brown color. 

 Then mount in Canada balsam. 



In these preparations the nerve cells and their nuclei appear deep brown ; 

 blood vessels and their nuclei of a lighter shade. Glia cells and nerve fibres 

 stand out sharply as a fine network. 



2. As the sliding apart of the cover-glasses is apt to disturb the relations of 

 the parts, the author recommends the following method : — A bit of the gray 

 substance, the size of a hemp seed, is placed between two cover-glasses, with 

 the addition of two or three pieces of thin paper placed at the edges. The 

 covers ai^e then pressed together as above. They are then placed in a solu- 

 tion of picro-carmine, or an aqueous solution of methyl blue. The stain pen- 

 etrates very slowly. At the end of two days a band of tissue, 2 mm. wide, 

 will only be stained ; at the end of four days this will have increased to 4 mm. 

 The cover-glasses are now removed from the staining fluid, washed in alcohol, 

 and dried. Under the microscope, the cell bodies will be seen slightly stained, 

 the nuclei of a darker shade, and the nucleoli of a still darker shade. The 

 nuclei of the glia cells will be found stained quite deep, while the interstitial 

 tissue will be colorless or very faintly stained. In many cases the cell bodies, 

 as well as the interstitial tissue, remain colorless. 



If the cover-glass preparations are allowed to remain in the staining fluid 

 for fifteen days, the whole of the thin layer of tissue will become stained.. At 

 the end of this time they are removed from the staining fluid, washed in al- 

 cohol, then placed in oil of cloves for four days ; then in xylol for two days, 

 and finally cemented on the surface of a slide with xylol dammar. 



Neutral Aniline Staining Fluid. J V. Babes. — This staining fluid con- 

 sists of saturated solution of orange 125 c.c, saturated solution of acid fuch- 

 sin in 200^ alcohol 125 c.c, alcohol 64 c.c, saturated solution of methyl 

 green 125 c.c. The orange and acid fuchsin solutions are fixed, and then the 

 alcohol and methyl green added gradually. 



Sections of tissues stained in this fluid show blood cells stained orange-yel- 

 low, nuclei of polynucleated leucocytes green, their cell bodies deep violet, cell 

 bodies of eosinophilous cells blackish-brown. 



*Zeitsch. f. Wiss. Mikros. iv, 1887, p. 499. 

 fZeitsch. f. Wiss. Mikros. iv, 1887, p. 467. 

 iArch. f. Path. Anat. u. Phys. cv, 1886, p. 526. 



