70 



EXPERIMENTAL PHARMACOLOGY 



Chloroform. (Action on the Frog's Heart.) 



2. Repeat the above experiment on a fresh frog using a 

 saturated solution of chloroform in normal salt solution 

 (solubility ==1 to 200). Does chloroform affect the nervous 

 inhibiting apparatus of the heart? What differences do you 

 note between ether and chloroform as regards their cardiac 

 action I 



3. Familiarize yourself with the anatomy of the frog's 

 heart (Fig. 65). How does the frog's circulatory apparatus 

 differ from that of a mammal? 



Dorsal. 



Ventral. 



LH posterior lymph u 



Fig. 66. Diagrammatic representation of the lymph spaces of the frog. 



(Modified from Ecker.j 



Chloroform. (Action on Lymph Hearts.) 



4. Allow a frog to sit in a good light with the lower end 

 of the urostyle turned toward a window. On each side of 

 the lower end of the urostyle (L.H. in Fig. 66) note a series 

 of feeble pulsations beneath the skin. This is caused by 

 the beating of the posterior pair of lymph hearts. (The 

 anterior pair of lymph hearts are located, one heart on 

 each side, between the transverse processes of the third 



