(d) Cross-Section of Voluntary Muscle. 



One of the small muscles of a mammal was hardened in a sat- 

 urated aqueous solution of mercuric chloride, stained in borax car- 

 mine, embedded in paraffin, and cross-sectioned. Fix to the slide, 

 and mount in balsam. 



Study first under low power. Observe the endomy- 

 sium and perimysium. Under high power note the struc- 

 ture of the muscle fibres and the areas of Cohnheim. 

 Observe the position of the muscle nuclei. Sketch under 

 high power. 



(e) Longitudinal Section of Injected Striped Mus- 



cle. 



The arteries of one of the extremities of a dog were injected 

 with a Berlin blue gelatine mass; the tissue was then hardened in 

 alcohol, stained in alum carmine, embedded in. paraffin, and sec- 

 tions cut parallel to the course of the fibres. Fix to the slide, and 

 mount in balsam. 



Study under low power. The muscle fibres are stained 

 with the alum carmine. Between and over the fibres are 

 tortuous blue threads, the injected capillaries, forming an 

 anastomosing network. Sketch as seen under low power. 



(f ) Cross-Section of Tongue. 



The tongue of a cat was hardened in absolute alcohol, stained 

 in Delafield's heematoxylin, embedded in paraffin, fixed to cover 

 glasses, and counter-stained in eosin. Mount in balsam. 



Study first under low power. Notice the striped mus- 

 cle fibres cut transversely, longitudinally, and obliquely. 

 The structure of the muscle -fibres will be more clearly 

 made out under high power. The nuclei are stained blue, 

 the muscle substance red. Sketch under low power. 



