STRIATED MUSCULAR TISSUE. DO 



It serves to afford contractility, especially to the organs of vegetative 

 life. 



Kill a good-sized frog by decapitation, and open the abdomen on 

 the median line. Fill the bladder with air, after the introduction of 

 a blowpipe into the vent. Remove the inflated bladder with a single 

 cut with the curved scissors, and place it in a saucer of water. Pro- 

 ceed to brush it, under the water, with two earners hair pencils so as 

 to remove all of the cells from the inner surface. It will bear vigor- 

 ous rubbing with one of the brushes, holding it at the same time with 

 the other. Transfer to alcohol for ten minutes, and afterward stain 

 with haema. and eosin. While in the oil, cut the tissue into small 

 pieces, and mount flat in dammar. Examine L. and H. 



Observe the bands of involuntary muscle crossing in various direc- 

 tions. You will distinguish (Fig. 47) between the muscle and the 

 connective tissue cells by their nuclei. 



STRIATED MUSCULAR TISSUE. 



A skeletal or striated muscle consists of cylindrical fibres, one-three 

 hundredth to one-six hundredth of an inch in diameter, and one to 

 two inches long. These primitive fibres are supported by a delicate, 



FIG. 48. DIAGRAM INDICATING THE MINUTE STRUCTURE OF STRIATED MUSCULAR FIBRE. 



A, A. Sarcolemma. 



B, Krause's line connecting with the sarcolemma and dividing the fibril into compartments. 



C, C. The rod-like contractile substance. 



D , Hensen's middle disc. 



