SPINAL CORD OF VERTEBRATA. 



275 



Spinal Cord with the large ganglia 

 contained within the cavity of the 

 cranium, is effected by means of 

 processes from its superior extre- 

 mity, the arrangement of which is 

 somewhat complex. This portion 

 of the cord, which also lies within 

 the cavity of the cranium, has been 

 termed the Medulla Oblongata. 

 It has been supposed to be the 

 peculiar seat of vitality ; but the 

 only real foundation of this idea 

 is, that it is the great centre of the 

 Respiratory actions, on the conti- 

 nuance of which all the other 

 functions are dependent. The 

 Brain may be removed from above, 

 and nearly the whole Spinal Cord 

 from below, without an immediate 

 check being put upon all the phe- 

 nomena of life. In this Medulla 

 Oblongata,ybz<r different parts may 

 be distinguished on each side: 1, 

 The Anterior Pyramids, or Cor- 

 pora Pyramidalia ; 2, The Oli- 

 vary Bodies, or Corpora Oliva- 

 ria; 3, The Restiforrn bodies, or 

 Corpora Restiformia ; otherwise 

 called Processus a Ccrebello ad 

 Medullam Oblongatam; 4, The 



[Fig. 137. 



[Fig. 136. 



A posterior superior view of the Pons Varolii, the 

 Cerebellum, and the Medulla Oblongata and Spinalis. 

 1, 1, the crura cerebri; 2, the pons varolii or tuber- 

 annularis; 3, its middle fossa; 4, an oblique band of 

 medullary matter seen passing from its side ; 5, the 

 external surface of the crus cerebelli in its natural 

 state ; 6, the same portion deprived of outer layer; 7, 

 the nervous matter which united it to 4; 8, the trige- 

 minus or fifth pair of nerves ; 9, portion of the audi- 

 tory nerve the while neurine is seen passing from 

 the oblique band which comes from the corpus resti- 

 forme to the trigeminus nerve in front, and the auditory 

 nerve behind ; 10, 11, the superior portion of the hemi- 

 spheres of the cerebellum; 12, lobulus amygdaloides ; 

 13, corpus olivare; 14, corpus pyramidale ; 15, medulla 

 spinalis.] 



[Fig. 138. 

 s 



Front view of the medulla oblon- 

 gata: p, p. Pyramidal bodies, de- 

 cussating at d. 0,0. Olivary bodies. 

 r,r. Restiform bodies, a, a. Arci- 

 form fibres, v. Lower fibres of the 

 Pons Varolii.] 



Posterior view of the medulla oblongata :pp. Posterior 

 pyramids, separated by the posterior fissure, rr. Restiform 

 bodies, composed of cc, posterior columns, and dd, lateral 

 part of the antero-lateral columns of the cord. aa. Olivary 

 columns, as seen on the floor of the fourth ventricle, sepa- 

 rated by s, the median fissure, and crossed by some fibres 

 of origin of nn, the seventh pair of nerves.] 



