Hardened specimens may also be stained with aniline blue-black, but the results are not to be compared with those obtained by the fresh method. The stain is usually diffuse, but this can be improved by placing the sections for 1/2 - 2 minutes in a 2 per cent. solution of chloral hydrate in distilled water after staining. *Golgi’s metallic stains* for nerve cells. Golgi introduced the methods of producing a metallic deposit of mercury or silver in the nerve cell, revealing both the cell and its processes. This method has been very fruitful in discoveries, especially in the hands of Ramon y Cajal, Köllicher, Van Gehucten and others. It gives best results with embryonic tissues. To ensure good results it is important that the tissue be removed immediately after death. Sections of brains removed some hours after death usually give disappointing results. There are several methods now in vogue, all slight modifications of Golgi’s original methods. *Silver nitrate method.*--Small pieces not more than a quarter of an inch cube, are transferred straight from the body to a large quantity of Marchi’s fluid (p. 24) and kept in it for about a week, or longer in the case of adult specimens. On removal from Marchi’s solution the tissue should be washed for a few seconds in distilled water, and then placed in a large quantity of a 3/4 per cent. solution of nitrate of silver solution in distilled water for at least a week. The lump of tissue becomes of a brick red colour owing to a coating of silver chromate. On removal from the silver solution the tissue should be washed in methylated spirit for a few minutes and the incrustation of silver chromate brushed off. Sections may be cut in gum and celloidin; or they may be fixed on a cork with celloidin or spirit varnish and cut without embedding: very thin sections are not required. Dehydrate in alcohol, clear in xylol, and mount in balsam. Goodall advises a mixture of pyridine and xylol for clearing, and mounts in strong xylol-dammar solution, without a cover-glass. Very careful attention to details and much practice are required before uniformly good results can be obtained. The results are extremely beautiful and well repay the labour expended on them. The cells and their processes appear black on a yellowish ground.