304 



NERVE-TISSUE. 



in a dark wine-yellow solution of bichromate of potash, or in 

 Miiller's fluid. Either of these liquids should be greatly in 

 excess compared with the bulk of the specimens. They will 

 preserve the nerve-tissue, if changed every fourth or fifth day, 

 or until the liquid remains clear. The hardening can be accom- 

 plished afterward by alcohol or a very weak (one-fifth to one- 

 tenth per cent.) solution of chromic acid. A slight excess of 

 chromic acid will soon render the nerve-tissue brittle and not 

 suitable for sections. 



JV" 



FIG. 130. INTERVERTEBRAL GANGLION OF A HUMAN EMBRYO, 

 EIGHT WEEKS OLD. 



G, partly solid, partly nucleated, plastids ; N, nerve-fibers, not yetmedullated ; M, delicate 

 rayxomatous connective tissue ; B, capillary blood-vessel, cut transversely. Magnified 600 

 <liameters. 



Sections made with razor, or other cutters, are alone appro- 

 priate, in my opinion, for study of this tissue. The teasing of 

 the tissue, which is unavoidable even with this mode of prepara- 

 tion, is the only teasing allowable, and may sometimes show 

 noteworthy characters. The thinness of the section is its main 

 value. By mounting in dilute glycerine the details will be 



