246 EXPERIMENTAL PHYSIOLOGY. 



5. The Lymph-Hearts. 



(a.) Destroy the brain of a frog, place it on its belly, and 

 watch the beating of the posterior pair of lymph-hearts, 

 which are situated one on each side of the urostyle (Fig. 113). 



(b.) Remove the skin covering them, taking care not to cut 

 too far outwards, else a cutaneous vein will be injured and 

 bleed freely. Count the number of beats per minute, noting 

 that the rhythm is not synchronous with the blood-heart, 

 whose movements can usually be distinguished without 

 opening the chest. 



(c.) Destroy the posterior part of the spinal cord with a 

 seeker or wire, and observe that the rhythmical automatic 

 movements of the lymph-hearts cease. 



