40 



cut ends, due to the transected fibrillae, and the muscle nuclei entad 

 of the sarcolemma. Can you recognize areas of Cohnheim ? The 

 transections of the fibers are of difiFerent sizes. This may or may 

 not mean a difierence in the caliber of the fibers. Why ? Compare 

 with 61. Vou may be shown transections stained with iron hema- 

 toxylin in which the fibrillae are better differentiated. 



CARDIAC MUSCLE. 



68. Muscle cells. Isolated in caustic 

 potash dissociator (§ 14) ; now in glycerin. Place a small drop of 

 the glycerin containing the cells upon the slide ; cover carefully ; 

 seal with shellac. 



Study the preparation, examining many cells and noting the 

 shape, the position of the nucleus or nuclei, the trans-striations, the 

 relation of the cells to each other, and their processes. 



69. Transection of myocardium. Human auricle or ven- 

 tricle. Assigned for study. Miiller's fluid ; paraffin ; sections 

 10 )J.. Stained with hematoxylin and picrofuchsin. 



Observe the shape and relation of the cells, the muscle columns 

 and fibrillae, and the position of the nucleus ; compare with the 

 transections of plain and striated muscle (61, 67). You may be 

 shown transections and longisections of cardiac muscle stained with 

 iron hematoxylin, in which the fibrillae and cross-striations are bet- 

 ter shown. 



