MUSCULAR SYSTEM. 



Q. Do the nerves proceed directly from the brain to 

 the muscles of animal life ? 



/?. Some do, but the greater number go from the me- 

 dulla spinalis. 



Q. What evidence is there that the nerves of motion 

 proceed from the medulla spinalis? 



./?. If the medulla spinalis is irritated, convulsions arise; 

 and as this irritation is higher or lower on the medulla, 

 are the superior or inferior parts irritated. 



Q. Why are injuries of this medulla, at its upper part, 

 so dangerous? 



.#. Because the functions of the diaphragm and inter- 

 costal muscles are destroyed. 



Q. What nerves go directly from the brain to the mus- 

 cles of animal life? 



Jl. Those to supply the tongue, face, and eyes, and 

 some others. 



Q. Are all the nerves of animal life equally disposed to 

 convey irritation from the brain? 



/?. No ; those of respiration are least so, and the wis- 

 dom of this is evident. The muscles of the extremities, 

 face, larynx, pelvis, abdomen, intercostals, and diaphragm, 

 are, in the order mentioned, disposed to take on irritation 

 from the brain. 



Q. In what direction is nervous influence propagated? 



/?. From the superior to the inferior part of the nerve 

 only. 



Q. What circumstances affecting the muscles, alter the 

 animal contractility of that texture? 



*ft. Inflammation, contusion, infiltration of serum; in- 

 terruption to the flow of blood, for the arterial motion, 

 and that conveying red blood, is necessary to muscular 



