NERVE MUSCLE PREPARATION. 



197 



FIG. 30. G Gastrocne- 

 mius. H S hook through 

 tendo achillis. F Femur. 

 S Sciatic nerve with 

 piece of spinal column C 

 attached. 



Make a hole through the latter for the introduction of an S hook 1 

 by passing the point of the scissors through it towards the subjacent 

 bone. Detach the tendon and sever it on the 

 tarsal side. 



Raise the gastrocnemius by means of the ten- 

 don and carefully avoid touching the muscle with 

 forceps. 



Clear the muscle up to the knee, and divide 

 this joint transversely with scissors, which can 

 be done without danger to the tibial nerve if the 

 muscle be turned well out of the way. 



Next clear the femur of all muscles excepting 

 the gastrocnemius, and sever the bone near the 

 hip joint. 



Divide the spinal column just above the attach- 

 ment of the nerves, and then mesially so as to 

 leave a portion attached to each sciatic plexus. 



Manipulate the nerve by means of this piece of bone and sever any 

 restraining tissue. 



Rapid preparation of a fpogr's limb. After stunning and pithing the 

 frog, hold it horizontally by the hind limbs with the left hand ; the fore part of the 

 body will hang forming a sharp angle where the spine meets the iliac bones. 



Pass one point of a pair of scissors through the skin under the middle of the 

 spinal column, and divide the back. The fore end will then hang down, held by the 

 skin on each side. Divide the latter the whole length of the abdominal cavity, and 

 then cut away the abdominal contents, taking care in doing so not to injure the nerves. 



Grasp the skin with a towel at its spinal end, and holding the spine with the 

 fingers of the other hand strip the skin off like an inverted glove, completely denuding 

 all the structures. 



Now grasp the muscles of the thigh between the dried finger and thumb of the 

 left hand so as to put the dorsal aspect on the stretch, and scratch through the 

 aponeurotic tissue until the nerve is exposed completely from knee to sciatic 

 opening, and complete the separation of the nerve and muscle as before. 



Cut away all the muscles from the femur, divide the latter at its upper end, raise 

 the limb by means of the foot so as to lift up the nerve, cut through all restraining 

 tissue, pass one blade of the scissors through the sciatic opening, divide the coccigeo 

 iliacus muscle and the iliac bone at both ends, lay the frog on its back, clear the 

 nerves to the spine, and divide the latter as before. 



Clear the gastrocnemius, insert the S hook and remove the leg as before. 



Obtained through Messrs. Reynolds & Branson, 'Commercial Street, Leeds. 



