5 



(d) Non-Madullated Nerve Fibres Stained in 



Haematoxylin. 



The splanchnic nerves of a dog were hardened in pirric acid, 

 and stained in Boehmer's hrematoxylin. Tease in gum glycerine. 



Examine under high power. The great majority of 

 the fibres are non-medullated, i. e., possess no medullary 

 sheath, and hence showing no nodes of Rauvier. Numer- 

 ous nuclei 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. 



The sciatic of a frog was hardened in a \% solution of osmic 

 acid saturated with picric acid for 24 hours, washed in 70% alco'iol 

 for 2 days, embedded in paraffin, and sectioned. Fix to the slide 

 and mount in balsam. 



Study under high power. The medullary sheath is 

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

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

 these are the ends of the primitive fibrillae. Sketch undor 

 high power. 



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



Anilin Blue and Safranin. 



The posterior tibial nerve (human) was hardened for several 

 weeks in Miiller's fluid, dehydrated, embedded in paraffin, and 

 sectioned. The sections were fixed to cover glasses, stained in 

 anilin blue andsafranin, dehydrated, and cleared in oil of bergamot 

 and xylol. 



The axis cylinders are stained blue, the myelin 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 surrounding 



