314 RETINA, INNER EAR, NERVKS. 



taining one or two drops of glacial acetic acid for each cubic centimetre, and 

 finally (without previous washing with water) are stained for fifteen to 

 twenty minutes in aqueous solution of China blue (the best China blue for 

 this purpose is that supplied by the Badische Anilin- und Soda-Fabrik, at 

 Stuttgart). They are washed out in alcohol, cleared in essence of turpentine, 

 and mounted in dammar. 



For the results, see the paper and the plate, I. c. 



PLATNEE (Zeit.f. wiss. Mile., vi, 2, 1889, p. 186) obtains a specific stain 

 of the neuroceratin framework of inedullated nerve in the following way : 

 small nerves are fixed and hardened for several days in a mixture of one part 

 of Liq. Ferri Perchlor. (Ph. G. Ed. ii) and three to four parts of water or 

 alcohol. They are then to be washed out in water or alcohol till no traces 

 of iron remain in them (the reaction of the washings with rhodanide of 

 potassium being a good test of this), and are stained for several days o r 

 weeks in a concentrated solution of "Echtgriin" (Di-nitroresorcin) in 75 

 per cent, alcohol ; after which they are dehydrated, imbedded, and sectioned. 



654. Axis Cylinders. 



KUPEFEK'S Method (Sitzb. math. phys. Kl. k. Bayr. Acad. 

 Wiss., 1884, p. 446; Zeit. f. wiss. Mik., 1885, p. 106). A 

 nerve is stretched on a cork and treated for twenty-four hours 

 with 0'5 per cent, osmic acid. It is then washed in water for 

 two hours and stained for twenty- four to twenty-eight hours 

 in saturated aqueous solution of Saurefiichsin ; after which it 

 is washed out for from six to twelve hours (not more in any 

 case) in absolute alcohol, cleared in clove oil, imbedded in 

 paraffin, and cut. Sections are said to show the axis cylinder 

 as a bundle of fibrils (stained red) floating in an albuminous 

 liquid. 



NISSL'S Method (Nunchener med. Wochenschr., 1886, p. 528; 

 Zeit. f. wiss. Mik., iii, 3, 1886, p. 398). Bichromate objects 

 to be treated as follows : Alcohol of 95 per cent. ; aqueous 

 solution of Congo red, of 5 : 400 strength, seventy-two hours ; 

 alcohol of 95 per cent., five to ten minutes; alcoholic solution 

 of nitric acid of 3 per cent, strength, six hours ; alcohol, five 

 minutes; clove oil ; balsam. 



EHRLICH'S Methylen Blue Method (Abh. k. Akad. Wiss. 

 Berlin, February 25th, 1885). It has been made out by 

 Ehrlich that by injecting living animals with methylen blue, 

 a specific stain of the axis cylinders of peripheral nerves may 

 be obtained. He found that the axis cylinders that are stained 

 sihvays belong to sensory nerves, motor nerves containing no 

 element that takes the stain. 



ARNSTEIN (Anat. Anz., 1887, p. 125), however, found that 



