HOW TO USE IT. 253 



Debore's Method.*— Place in a 4 per cent, solution of bichro- 

 mate of ammonia for three weeks, then in a solution of phrenic 

 gum for three days, and for three days more in alcohol. Cut 

 sections and place in water to prevent curling ; immerse in a satu- 

 rated solution of picric acid for twenty-four hours, and colour with 

 carmine for about twenty minutes, the picric acid acting as a 

 mordant. 



Double Stain for Nervous System-f— Sections — which should 

 not be in water for more than five to ten minutes after cutting — 

 should be placed for several hours in a concentrated watery solu- 

 tion of methylin-blue ; wash in water and transfer to a saturated 

 watery solution of acid fuchsin for about five minutes. Quickly 

 wash in water, and place for a few seconds in i per cent, alcoholic 

 solution of caustic potash, and wash in a large quantity of water. 

 Gerlach's network of delicate fibres stain blue or violet on red 

 ground. 



Prof. Adamkiewicz's Method is to stain with saffranin and 

 methylin-blue when individual segments are to be differentiated 

 and mount as usual for anilins. 



Staining Axis Cylinder of Medullated Nerve-Fibres. — Fix the 



nerve on a cork, and place for two hours in a J per cent, solution 

 of osmic acid ; wash for two hours in distilled water ; stain for 

 twenty-four to twenty-eight hours in a saturated solution of acid 

 fuchsin ; wash for six to twelve hours in absolute alcohol, clarified 

 with oil of cloves, imbed in parafiin, and cut. 



An excellent method, and one which gives very satisfactory 

 results, is that which is used by Dr. C. Robertson, Demonstrator 

 of Anatomy, Oxford. Place portions of ivarin cord, about i in. 

 long, in spirit (10 over proof) from four to five hours ; transfer to 

 a 6 per cent, solution of bichromate of potash for six days, care 

 being taken during the process of hardening to remove with a 

 razor thin sections from the ends to allow the solution to tho- 

 roughly penetrate to the interior of each piece. Transfer to weak 

 spirit for two days, then to strong for two or three more days, when 



* "Archives de Neurolgie." 

 t " Zeitschr. f. Weis. Mikr.," Vol. II., 1885. 



