416 



ADVANCED PHYSIOLOGY 



Page 278. To show the relation of muscle to nerve, tetanus, etc., 

 destroy the brain of a frog, remove the skin of the upper part of the hind 

 leg, and by pulling apart the muscles locate the large sciatic nerve. By 

 stimulating the nerve the muscles of the leg will contract. For more 

 careful study proceed as follows : Follow the nerve carefully without 

 stretching or even touching it any more than necessary through the hip 

 joint to its exit from the spinal cord in the middle of the back; cut it 

 there, carefully get it free from the surrounding tissues, and coil it up 

 (two inches or so in length) on the muscle at the knee joint. Do not allow 

 it to lie on the skin of the lower leg. Now remove the muscles from the 

 thigh region, reserving the femur bone ; cut the latter off near the hip, 

 and clamp in a holder supported on a standard. Place the nerve on a 

 pair of electrodes which are connected with a key and cells in an electric 

 battery circuit, taking care all the time not to let the nerve get dry ; mois- 

 ten with 0.6% salt (NaCl) solution, with camel's hair brush. By opening 

 and closing the key, a single or often repeated stimulus can be sent into 

 the nerve, and the characteristic effect on the muscle noted. 



Figure showing simplest possible scheme of apparatus for using 



nerve-muscle preparation. 

 B = battery E = electrodes 



K = key N= nerve 1A7* 



w = circuit wires M= muscle \\ 



W=* weight 



Page 281. Microscopic preparations of smooth muscle which have 

 been properly stained are most satisfactory for examination. Unless 

 there is at hand special apparatus, it is not easy to show the normal reac- 

 tion to stimuli of smooth muscle. So, too, its involuntary rhythmic con- 

 tractions cannot be easily demonstrated unless, if taken from intestine of 

 warm-blooded animal, it be maintained at the full body temperature in 



