54 THE STRUCTURE OF A NERVOUS SYSTEM. 



Man it is about 40 to 1. Thus, whilst the Cerebrum 

 and the Cerebellum, which together constitute the Brain, 

 is actually much lighter in the Lamprey than the Spinal 

 Cord, these same parts in Man are found to attain com- 

 paratively enormous dimensions, and greatly to exceed in 

 weight the inferior, though highly important, spinal 

 centres. 



