72 THE NERVOUS SYSTEM. 



4. The apparatus; of motion is composed of the muscles, of the 

 bones, and of some other organs. 



APPARATUS OF THE SENSATIONS. 



5. Sensibility is the faculty of receiving impressions from sur- 

 rounding objects. 



6 This faculty has its seat in a particular apparatus called the 

 NERVOUS SYSTEM. 



7. It is also through the medium of this nervous system that 

 motion t ikes place, that the influence of the WILL makes itself felt 

 in different parts of the body, and that the phenomena of intelli- 

 gence is manifested. 



8. We distinguish in this apparatus two principal parts, which 

 are called the nervous system of animal life, and the nervous 

 system of organic life. 



9. The iiervonx system of animal life presides over the func- 

 tions of the life of relation ; it is also called the cerebro-spinat 

 sy*t<>ni, because the brain and spinal marrow are the most impor- 

 tant parts of it. (page 73 /?>/, 25.) 



10. The term eiice/ilta/oii, is applied to the great nervous mass 

 formed by these two organs and the other central parts of the 

 nervous system, lodged in the cavity of the cranium and in the 

 canal which exists in the whole length of the vertebral column. 



11. The cranium is a great cavity which occupies all the supe- 

 rior and posterior parts of the head, and which at the inferior part 

 or base, presents several holes. One of these holes, which is very 

 much larger than the other and placed a little behind, gives it a 

 communication with the veitcbm I canal. 



1*2. The vertebral canal is a cavity hollowed out in the verte- 

 bral column or spine, of which it occupies the whole length ; it 

 consequently descends from the head, all along- the back to the 

 lowest extremity of the trunk and even into the tail, when the 

 animal is provided with an appendix of this sort. 



4. What constitutes the apparatus of motion? 



5. What is sensibility' 



6. Upon what does sensibility depend ? 



7. Through what means is the influence of the WILL conveyed to di 

 ferent parts of the bo iy ? 



8. What are the principal parts into which the apparatus of sensation is 

 divided ? 



9. What is the office of the nervous system of animal life ? WLj is it 

 called the cercbro-spinal system ? 



10. What is meant by the term encephalou? 



11. What is the cranium ? 



12. What is the vertebral canal? 



