142 Practical Zoology. 



the vein toward the head, watching the bulgings. Dissect out 

 the jugular vein from the head to the shoulder ; insert the nozzle 

 of a syringe, first into one end and then into the other, and 

 show the effect of forcing currents in each direction. Cut the 

 vein open along one side, pin inside out to a piece of a shingle, 

 and examine the thin, pocketlike valves. Test the elasticity of 

 the vein. Note the smoothness of its inner coat. Remove a 

 piece of an artery and experiment in the same way with it. 



THE KIDNEY. 



The structure of the rabbit's kidney may be made out by the 

 following directions, but the sheep's kidney, being larger and 

 essentially similar, may be conveniently used. If the sheep 

 kidney be used, its dissection may be made later. 



1. Observe the depression in the inner border of the kidney, 

 the hilum. 



2. From the hilum trace a slender white tube, the ureter, back 

 to the bladder. Find also the renal artery and vein, branching 

 as they enter the kidney through the hilum. 



3. With a sharp knife split the kidney like a bean, beginning 

 at the outer border, stopping the cut when a white membrane is 

 reached near the hilum. With forceps pry about to explore the 

 cavity between this white membrane and the body of the kidney. 

 Note the branches of this cavity into the kidney. Note also the 

 extension of the white membrane into these cavities. Make out 

 that the blood tubes extend through these white branches to the 

 outer parts of the kidney. Count these branches. 



4. In the center of the white membrane find the opening of 

 the ureter, by which the urine is conveyed to the bladder. Pass 

 a probe through this opening into the ureter. 



5. Note the difference in color of the outer and inner parts of 

 the kidney. At the line of change of color find where the blood 

 tubes first branch into the real kidney substance. Examine 

 carefully the cut surface of the kidney to see its markings. 



