'd> Non-M3:liillated Nerve Fibres Stained in 

 Haematoxylin. 



Tlie .siilaiiihiiic nerves of a doj: were liardened in picric acid, 

 and stained in Boeliiner'.s lia'niatoxylin. Tease in gum ylyi eriiie. 



Examine under liigli power. The great majority of 

 the hbres are non-medullated, i. e., possess no medulhirv 

 sheath, and lience showing no nodes of Ranvier. Numer- 

 ous nuelei will be seen, often giving the fibre a be ded 

 appearance. Sketch under high power. 



(e) Cross-Section of a Nerve Trunk Hardened in 



Osmic Acid. 



Tiie Kfiatii- of a froy was liardencd in a ]% solution of osniio 

 acid satiu'ated with picric acid for 24 liours, vvasiied in 70'\) alro'iol 

 for 2 days, embedded in parattin, and sectioned. Fix to tiie slide 

 and mount in balsam. 



Study under liigh power. The medullary sheath is 

 stained black, and the axis cylinder a grayish-blaek. Now 

 and then fine granules can be seen in the axis cylinder; 

 these are the ends of the primitive fibrillae. Sketch und^r 

 high power. 



(f) Cross-Section of a Nerve Trunk Stained in 



Anilin Blue and Safranin. 



The posterior til)ial nerve Ominan) was hardened for several 

 weeks in Midler's fluid, dehydrated, embedded in parattin, and 

 sectione<l. The sections were fixed to cover jrlasses, stained in 

 anilin hlue and safranin, deliydrate<I, and cleared in oil of berganiot 

 and xylol. 



The axis cylinders are stained blue, the mj^elin orange, 

 and the nuclei red. Study under low^ power. Note that 

 the funiculi are held together by a loose connective tissue, 

 the epineurium ; in it groups of fat cells and the blood 

 vessels of the nerve trunk are found. Each funiculus is 

 surrounded by a dense connective tissue sheath, the peri- 

 neurium ; this shows a lamellar structure. The nerve fibres 

 in cross section should be studied under high power. 

 Between the nerve fibres of a funiculus a small amount of 

 connective tissue is seen, the endoneurium. Draw under 

 low power a number of funiculi, and the surroundins: 



