XVIII.] 



NERVE-GANGLIA, NERVE-CELLS, ETC. 



Capillary; V. Vein; K. Capsule; 



N ' Nerve - cell > x 3- 



and subsequently in alcohol. Make transverse sections. Stain in 

 picro-carmine or a watery solution of nigrosin (several hours), and 

 mount the former in Farrant's solution, and the latter in balsam. 



(a.) Observe the fibrous capsule of the ganglion ending in 

 septa, and numerous bundles of non-medullated nerve-fibres cut 

 obliquely or transversely. A few blood-vessels. 



(/>.) The nerve-cells, each with a capsule, showing nuclei. The 

 nucleated cell substance is frequently somewhat shrunk from its 

 capsule, and at one side it usually 

 contains some yellowish-brown pig- 

 ment granules, especially if the 

 human cervical ganglion be used. 

 It is difficult to see the process, 

 which becomes continuous with 

 a nerve-fibre, but with care it may 

 be seen passing out of one or more 

 of the cells (fig. 201). 



(c. ) The veins have long fusiform 

 dilatations upon them ; this is not 

 unfrequently seen in teased prepara- 

 tions of a human ganglion, but can 

 only be fully demonstrated in an 

 injected specimen of the ganglion. 



9. Isolated Multipolar Nerve-Cells of the Spinal Cord. 

 There are several ways of preparing these. 



(i.) Cut out a small part of the anterior cornu of the spinal 

 < 4 .ml of an ox, calf, sheep, or other animal, and place it in very 

 dilute chromic acid (.01 per cent.) or .2 per cent, potassium 

 bichromate for a few days, and do not change the fluid. Wash, 

 and place it for twenty-four hours in strong carmine solution 

 (p. 63). Place a little of the red pulp on a slide, and, with the 

 aid of a dissecting microscope, try to isolate one or more multi- 

 polar nerve-cells. 



(ii.) Or, what is a better method, take small fragments of the 

 anterior cornu of the spinal cord of an ox or calf, and place them 

 in dilute alcohol for forty-eight hours or longer. After this time 

 we can see better the distinction between the grey and the white 

 matter. Shake the fragments in the dilute alcohol, and allow the 

 debris to subside. Pour off the alcohol, and "fix" the cells with 

 .25 per cent, osmic acid (one hour); pour this off, and stain the 

 cells for forty-eight hours with picro-carminc. Pour off the picro- 

 carmine and replace it by glycerine-jelly. When the glycerine- 

 jelly is warmed, a drop of the fluid placed on a slide is almost 

 certain to contain one or more isolated multipolar nerve-cells. 



With a low power find a cell. 



