STAINING, PRACTICAL AND THEORETICAL 



5. Wash in distilled water; then fix in Solution D. 



6. Wash thoroughly in tap water. 



7. Dehydrate; clear and mount. 



Results: 



Astrocytes: black. Nerve cells: red. Nerve fibres: unstained. 

 Background: light brownish purple, or unstained. 



References : 

 Cajal, S. Ramon y (1913, 1916, 1920). 

 Conn, H. J. & Darrow, M. A. (i947)- 

 Jones, Ruth McClung (1950), pp. 407-413. 



GOLGI METHOD (Rapid) 

 For nerve cells 



Solutions required: 



A. Potass, dichromate 3% . . . . 40 ml. 

 Osmic acid 1% 10 ml. 



This solution must be freshly prepared. 



B. Silver nitrate 0-75%. 



Technique: 



1. Immediately the animal is killed, tissues are cut into slices 

 about 2 mm. thick and fixed in Solution A for one to three days 

 depending upon the size of the pieces. 



2. After removing excess fixative by blotting, the tissues are 

 rinsed in Solution B until no more precipitate is formed. 



3. Transfer to a fresh lot of Solution B and leave for two days 

 or longer. 



4. With a camel-hair brush carefully brush the precipitate from 

 the surface of the tissue ; then wash well in distilled water. 



5. Dehydrate by immersing for one to four hours, depending 

 upon the size of the pieces, in each of the following: two lots of 

 95% alcohol; two lots of absolute alcohol; one lot of ether- 

 alcohol (equal vols, ether and absolute alcohol). 



6. Embed in Celloidin or L.V.N. 



7. Sections 60-100/* are mounted on slides and covered with 

 Canada balsam in benzol or cristalite, without cover glasses 

 {see L.V.N, technique). 



222 



