114- PHACTICAL HISTOLOGY [XIV 



anterior rami of the superior cervical ganglion of the cat have 

 many. 



Nerve stained with nitrate of silver. In teased fibres treated 

 with silver nitrate, a 'bicone' may be seen at the nodes ; this is a 

 stained mass around the axis tapering off on either side away 

 from the nodal region. 



On irrigating teased fibres with 0*1 p.c. sodium hydrate, the 

 nerve inside the neurilemma swells up, and the medulla flows 

 out from the cut ends of the fibres ; there is no appearance of 

 any special resistance to the flow, such as would be caused by 

 partitions, either at the breaks or at the nodes. 



Staining of axis cylinder, (a) The nerve is stretched and 

 placed in Flemming's fluid for 1 to 6 days ; washed for a day in 

 running water, stained for 1 to 3 days in -5 p.c. aqueous solution 

 of saffranin ; excess of stain extracted for a short time with 

 95 p.c. alcohol; then teased in glycerine containing a little 

 saffranin. (6) The stretched nerve is placed in 10 p.c. aqueous 

 or alcoholic solution of ferric chloride for one or more days, 

 thoroughly washed, placed in a saturated solution of dinitroso- 

 resorcin in 75 p.c. alcohol for 3 or more days, then teased out, 

 or imbedded and cut. Both methods are used for degenerating 

 pnd regenerating nerves. 



Fibrillar structure of axis cylinder. Engelmann recommends 

 irrigating the fresh nerve fibres of a frog with -2 p.c. silver 

 nitrate. The following method is given by Kuppfer ; the nerve 

 is stretched, placed in -5 p.c. osmic acid for 4 hours, washed with 

 water, placed in saturated aqueous solution of acid magenta for a 

 day, absolute alcohol 1 to 3 days, imbedded and cut ; the trans- 

 verse sections of the axis cylinders show small deeply stained 

 dots. Neither preparation is very convincing. 



Neurokeratin network. Place pieces of nerve in absolute 

 alcohol for a day, boil in the alcohol on a water bath for about 

 15 minutes and place in ether for a day. Part should be stained 

 with hsematoxylin, and part with osmic acid. The pieces may 

 be kept in clove oil. 



