XII.] STRUCTURE OF BLOOD-VESSELS. 135 



be well seen in this or in the mesentery, in these 

 further the oedema will be more obvious. To 

 observe the circulation in the mesentery, place 

 the frog on its back, cut through the skin and 

 abdominal muscles on one side, draw out and 

 pin over the stage a loop of the mesentery. 



DEMONSTRATION. 



Circulation in the mylo-hyoid muscle of the frog. 



