Histology; normal and morbid.
- Dunham, Edward K. (Edward Kellogg), 1860-1922
- Date:
- 1898
Licence: Public Domain Mark
Credit: Histology; normal and morbid. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![fibres a dark blue, nearly black, color. If it has been preceded by a stain with neutral carmine, the axis-cylinders of th(,' nerve-fibres will l)c stained red, and the nuclei of tiie nerve-cells will also appear red. 14. Golgi's Methods.—These methods have yielded most excel- lent results in the study of the central nervous system, the dis- tribution of the peripheral nerves, an<l the delicate terminations of the ducts of glands; c.(/., the bile-capillaries. The methods must be regarded as special procedures in such studies, and can but be referred to here. They all depend upon hardening in some chromium salt, with or without the addition of osmic acid, and the subsequent impregnation with silver nitrate. A precipitate is thus produced on or within certain of the elements in the specimen, giving them a dark-brown or black color. The methods are capricious, and not all of the tissue-elements of like character in the specimen are rendered prominent. This is an advantage, but necessitates a degree of care in the interpretation of the results. Furthermore, irrelevant precipitates may form in the tissues which have no definite relations to any structure. Considerable practice is, there- fore, required for the successful employment of all these methods, not only for a satisfactory execution of the manipulations, but also in the study of the results. The methods have no value for the study of cell-structure, since the whole cell is either covered or filled with the precipitates formed during the impregnation with silver. Golgi has divided his methods into three groups: the slow, the ra])id, and the mixed. For the details of these methods and of the various modifications introduced by different investigators the student is referred to the journals on microscopy. It must suffice to state here that the slow method begins with a hardenine: of the tissues in a 2 per cent, solution of potassium bichromate, which is gradually raised to 5 per cent. This hardening takes from fifteen days to three months. In the rapid method the tissues are first hardened in a mixture of 4 parts of a 2 per cent, solution of potas- sium bichromate and 1 part of a 1 per cent, solution of osmic acid. The tissues remain in this mixture for from two to six days, when they are ready for im])regnation. For either method the pieces of tissue should not be thicker than 1.5 cm.](https://iiif.wellcomecollection.org/image/b21223841_0423.jp2/full/800%2C/0/default.jpg)
