104 The microscope 



very well, and a double stain of eosin and hsematoxylin is 

 excellent. 



Dog. — Some sections should be made as soon as the cord has 

 been hardened in the Erlicki's fluid, before placing the cord in 

 alcohol; in order that they may be stained in osmic acid ; others I 

 find give good results if the sections be placed in o'5 per cent, 

 methyl green for 1 2 hours ; wash well in distilled water, then place 

 in borax carmine. This shows the axis cylinder and ganglion 

 cells red, whilst the neuroglia comes out violet, the remainder green. 

 Erlicki washes his sections for two hours in distilled water before 

 staining in ammonia carmine. 



Horse. — Get some short transverse sections and place for 

 forty-eight hours in Ranvier's alcohol. Then snip pieces out of 

 the anterior horn of grey matter, place in 2 per cent, solution 

 ot i)icro-carmine for twelve hours or so, then tease the 

 multipolar nerve-cells out with needles and mount in Farrant, in 

 a shallow cell. 



To harden Spinal Cord and Brain in Erlicki's Fluid.— 



It takes about ten days, but will do so in half the time if we care 

 to take the trouble to keep it at a temperature of about 40 deg. 

 C. or 104 deg. F. It must be fresh each time and filtered before 

 use. It must be changed daily or nearly so, and when the tissues 

 are hard enough the fluid is washed away with tap water and the 

 tissues finished in alcohol, commencing with 75 per cent. 



Spinal Cord (Overlach's Method).— Place small pieces of the 

 spinal cord of a child in a 1 or 2 per cent, solution of ammonium 

 bichromate until hard (fifteen to twenty days) in a cool place. 

 Make sections, and place in a solution of chloride of gold, i part, 

 and potassium in 10,000 parts of water, which has been acidu- 

 lated by the addition of a few drops of hydrochloric acid. Then 

 wash in one part of hydrochloric acid in 2,000 — 3,000 parts of 

 water; then transfer for 10 minutes to a mixture of one part of 

 hydrochloric acid in 1,000 parts of ordinary alcohol ; then succes- 

 sively in absolute alcohol, oil of cloves, and Canada balsam. 

 After three or four hours the nerve network is visible. 



Krause's Method.— Hang fresh cord in a cylinder full of 

 Mviller's fluid. Attach a small weight to the lower end to avoid 

 torsion. After twenty-four hours, change Miiller for i per cent, of 



