Laboratory Hints from the Literature: A Department Devoted to Abstracts of Books and Papers from Other Journals Dealing with Stains and Microscopic Technic in General

A technique which should be generally applicable for preparing permanent mounts of tissue cleared in Herr's four-and-a-half clearing fluid is described. This technique involves transferring plant or animal tissues through a series of solutions consisting of Pienarr's fixative, Herr's clearing fluid, chloral hydrate, acetone and finally polyester resin for mounting. Material prepared using this method is exceptionally transparent and well preserved, and is suitable for either phase contrast or Nomarski interference microscopy.     

Laboratory Hints from the Literature: A Department Devoted To Abstracts Of Books and Papers From Other Joubnals Dealing With Stains and Microscopic Technic In General

Lesions produced in the cerebral cortex of rats were studied by Nauta's method for degeneration. The brains were perfused with physiological NaCl solution, followed by 10% neutral (CaCO₃) formalin. The brains were removed and stored in the formalin for 2 wk to 1 yr. Experimental modifications of the staining method showed that its sensitivity for fine degenerating fibers could he enhanced by the following changes: (a) omitting 0.05% potassium permanganate; (b) replacing the hydroquinone-oxalic acid mixture with 0.1% pyrogallol. Procedure: (1) frozen sections to water; (2) 0.5% phosphomolybdic acid, 45 min; (3) distilled water, 1 min; (4) 0.1% pyrogallol (aq.), 2 min; (5) distilled water, 3 washes of 1 min each; (6) 1.5% silver nitrate (aq.), 30 min; (7) distilled water, 1 min, (8) Laidlaw's ammoniated silver carbonate, 10110 sec; (9) Nauta's reducer, 1-2 min; (10) distilled water, 1 min; (11) 1.0% Na₂S₂O₃, 2 min; (12) distilled water 3 changes, 1 min each; (13) dehydrate, clear, and cover. This method gave equally good results on degenerating axons in both cortex and thalamus.     

Laboratory Hints from the Literature: A Department Devoted to Abstracts Op Books and Papers from other Journals Dealing with Stains and Microscopic Technic in General

A 0.5% solution of sodium rhodizonate stains lead precipitates, obtained in histochemical methods for enzymes, in a brown-black shade. The precipitate obtained in the method for acid phosphatase can be stained directly; those obtained in the methods for alkaline phosphatase and lipase, after conversion into the corresponding lead salts.