XXX.] 



SPINAL CORD. 



347 



grey matter, and end free in fine branches without forming connections with 



nerve-cells. The fibres give off at 



right angles to their course fine fibrils 



collaterals which enter the grey 



matter, divide into fibrils, and end 



free. 



27. Degeneration of the Cord 

 (a. ) Method of March! for degenera- 

 tion, in central nervous system or in 

 nerves (Lesson XVII.) : 



(1.) Harden very small pieces of a 

 nerve or spinal cord either of 

 which is undergoing degenera- 

 tion in Miiller's fluid for at 

 least 8 days. 



(2.) Place for 6 days in the follow- 

 ing : 



Miiller's fluid . . 2 parts. 



Osmic acid (i per cent.) I part. 



(3.) Wash in water, harden in 



alcohol. 

 (4.) Embed and cut in celloidiu. 



All degenerated parts appear black, 

 all the others light grey or yellowish 

 (see p. 212). 



(6.) Wcigert's hsematoxylin method FIG. 322. L.S. of the Cord of the Cervical 



may be used for the same purpose. Region of an Embryo Sheep (22 cm long), 



rp, J i i C1 to show division of posterior roots after 



The degenerated fibres are unstained, entering the spinal cord. 

 i.e., on differentiating the section 

 the degenerated purls rapidly give up their stain, and thus appear unstained. 



LESSON XXXI. 



MEDULLA OBLONGATA CEREBELLUM- 

 CEREBRUM. 



MEDULLA OBLONGATA OE BULB. 



THE medulla oblongata is hardened in the same way as the cord. 

 T.S. are made at different levels, and stained in the same way 

 as the cord (L and H). 



1. T.S. Decussation of Pyramids. 



