38 



macerated in nitric acid dissociator. Demonstrate the outer longi- 

 tudinal and inner circular coats, observing the relative thickness of 

 each. Tease out upon a slide the end of a piece of the longitudinal 

 coat, fraying the end with a needle, and spreading it out like a fan ; 

 cover in a drop of water and examine. Observe the course of the 

 fibers (cells) and their relation to each other. Compare with the 

 longisection and transection in 6i. 



6i. Transection and longisection of plain muscle. Cat. 

 Transection of the intestine. Picric alcohol ; paraffin ; sections 

 fi. Stain with hematoxylin 15 minutes, eosin j/2 minute. 

 Mount in balsam. 



The outer muscular coat will afford a transection of plain muscle, 

 the inner cOat a longisection. In the outer coat, note the variation 

 in the size of the sections of different fibers ; and the occurrence of 

 nuclei in only a few ; why is this ? Compare the section of the inner 

 coat with the appearance found in 60. Study well the general 

 structural appearance of plain muscle in section ; what are the stain- 

 ing reactions of muscle and connective tissue with picrofuchsin ? 



STRIATED MUSCI<E. 



62. Fresh muscle fibers. Frog. Tease out upon a slide 

 in normal salt solution a small shred of the muscle from the leg of a 

 frog. Apply a cover glass and examine. 



Observe the semi-translucent appearance of the fresh muscle. 

 With a }i objective study the individual fibers, noting the trans- 

 verse striations. Here and there broken fibers may be found ; ex- 

 amine the broken ends to detect the torn sarcolemma. Lift the 

 cover and add a drop of 2% acetic acid, and note the effect upon the 

 fibers in bringing out sharply the muscle nuclei. 



63. Stained muscle fibers. Macerated in acetic 

 acid and glycerin and stained with Ehrlich's hematoxylin (Sihler's 

 method). Now in thin balsam. Carefully separate the individual 

 fibers of the muscle, keeping them parallel with each other and 

 tearing them as little as possible. Mount in balsam. 



The transverse striations and the muscle nuclei will show with 

 great clearness. Note also the difference in caliber of different 

 fibers. 



