LESSON XXIX. 



SPINAL COED. 



Make transverse sections of the hardened spinal 

 cord of a cat or dog through the region of 

 the cervical enlargement (say at the origin of 

 the 5th cervical nerve). Stain the sections with 

 dilute carmine or picrocarmine for a day, clear 

 and mount in Canada balsam. 



The cord should have been placed in ammonimn or 

 potassium bichromate 2 p.o. for three or four weeks, 

 then washed with water, placed in 30 p.o. alcohol 

 for several days changing the fluid each day, then 

 placed in 50 p.c. alcohol, which should be renewed 

 untU it no longer becomes coloured. The cord may 

 be kept in 75 p.c. or in strong alcohol. It is best 

 stained by placing the piece to be cut in strong 

 Frey's carmine for several days, it may then be 

 well washed with water, soaked in gum for a day, 

 and cut with the freezing microtome. 



Observe under a low power the following general 

 features 



a. The pia mater^ surrounding the cord; it 

 consists of two coats (cp. § 3 a); the inner 



