THE BRAIN. 1 C^) 



It has, however, the largest cerebrum in proportion to the 

 medulla oblongata and spinalis*, with the single and indeed 

 singular exception of the dolphin. 



It has the deepest and most numerous convolutions, ap- 

 parently in consequence of its size, as the purpose of this 

 structure seems to be that of affording a more extensive sur- 

 face for the application of the vascular membrane, the pia 

 mater. The convolutions become fewer and shallower as 

 the brain diminishes in size: there are none in the rodentia; 

 none in very small brains. 



It has the greatest quantity of medullary substance in pro- 

 portion to the cortical. In the foetus, the cortical is much 

 more abundant than in the adult. 



SoEMMERRiNG has shewu that that curious structure, the 

 sandy or earthy matter of the pineal gland (acervulus pine- 

 alis), belongs to the healthy natural state of the human brain, 

 being found from the fourteenth year ; and that it is almost 

 confined to manf. He found it, however, once in the 

 fallow-deer (cervus dama) ; and Malacarne J met with it 

 in the goat. An instance communicated by Caldani, of 



The VVenzei.s, whose accuracy seems to deserve the great- 

 est confidence, represent some of these proportions differently. 

 They have found the cerehrum, compared to the cerehellum, to he 

 in man, as 6AV— S^^St to 1 j in the horse, 4| to 1 ; cow, 5i-H 

 to 1 j dog, 6,V to 1 ; cat, 4-rV to 1 ? mole, 3f to 1 j mouse, 6i 

 to 1. Lib. cit. tab. iv. 



♦ The breadth of the medulla oblongata behind the pons Varolii, compared 

 to the greatest breadth of the brain, is, 

 In Man, as 1 — 7 



Simla' sinica (Bonnet ? j 4 



Chinois) c... J 



S. Cynomolgus. . . . > 1 — 5 



Dog 6-— 11 or 3— S 



Cat 8—22 



Rabbit 3_8— 1— 3 



Pig 5—7 



Sheep 5—7 



Roe 1—3 



Cow 5—13 



Calf 2—5 



Horse 8—21 



Dolphin 1—13 



In the latter animal, the breadth of the brain is twice its len;^th : — a pro- 

 portion, of which there is no other Instance in the animal kingdom. 



f De Lapillis vel prope vel intra Glandulam Pinealcrn sitis ; Mogunt. 1785. 



X Encefclotomia tValeum Quadiupuli, p. 31. 



