CHAPTER IV 

 The Muscle-Nerve Preparation 



THE central nervous system of a frog is destroyed by cutting through 

 the spinal cord at the occipito-atlantoid ligament and passing a blanket 

 pin into the skull and down the cord. Notice that the muscles of the 



Cut pectoral girdle. 



Small intestine. 



Testicle. 

 Rectum. 

 - Bladder. 



FIG. 27. Viscera of frog. The liver is shown in outline, and the 

 parts concealed by it are indicated by dotted lines. 



trunk and limbs are thrown into contraction when the cord is being 

 destroyed. Make a circular incision round the trunk just below the 

 upper limbs through the skin only, and, seizing the skin covering the 

 lower part, strip it off from both hind limbs. Lay the frog on its back 



