SYSTEMATIC SYNTHESIS OF TISSUES INTO ORGANS. 271 



646. THE CEREBRUM, VIEWED AT THE SIDE, EXHIBITS 

 by its form three divisions, called the anterior, middle, 

 and posterior lobes, only superficial, not corresponding 

 to any uses, and only serving as convenient designations. 



647. Below, about the centre of the cerebrum, and 

 at the front of the cerebellum, the spinal cord (Fig. 45) 

 is seen, called, while in the cranium, THE MEDULLA 

 OBLONGATA (oblongated marrow). 



648. IF THE CRANIUM HAD BEEN INVERTED, AND THE 



LOWER PART REMOVED, many nerves, their sheath, and 

 arteries must have been severed, and the spinal cord cut 

 across, and instead of the general spherical form of the 

 upper surface, a very uneven general surface of the cere- 

 brum would have been presented, as in the subjoined 

 figure, representing the base of the brains turned up- 

 ward and the cushion (subarachnoidean texture) removed. 



FIG. 188. 



Fig. 188. In this 

 view, the cerebellum, 7, 

 is seen above the back 

 part (posterior lobe) of 

 the cerebrum and the 

 shelf between them ; 

 the oblongata, 30, is in 

 view ; also the pons, 16, 

 and the commence- 

 ments of 12 pairs of 

 nerves ; 1, 2, is the an- 

 terior and posterior part 

 of the deep fissure near- 

 ly dividing the cerebri ; 

 3, anterior, 4, middle 

 lobes ; the convolu- 

 tions of the under sur- 

 face of which are evi- 

 dently numerous, as 

 they also are above 

 the cerebellum. 



646. What does ? 647. What is ? 648. What would have been presented 

 ? Describe Fig. 188. 



