33 



arc woven out of nervous fibres, and wholly consist 

 of them. 



21. The brain is divided into four ventricles. Near 

 the rise of the fourth, there is a round hole, over 

 which is suspended the pineal gland, so called from 

 its resembling the shape of a pine-apple. It is furnish- 

 ed with veins and arteries, and enclosed in a thin 

 membrane, derived from the pia mater. Des Cartes 

 imagined this to be the seat of the soul, but without 

 any solid reason. Nor has any one yet been able to 

 discover, what is the use of it. Is it such a reser- 

 voir of blood for extraordinary occasions^ as some ima- 

 gine the spleen to be? 



The brain is abundantly bigger in proportion in man 

 than in other animals. In other animals it is com. 

 monly biggest, caster is paribus, in those thathaye most 

 sagacity. 



There are in the brain multitudes of vessels so ex- 

 tremely small, that if a globule of blood, (a million. 

 of which exceed not a grain of sand in bigness) were 

 divided into 500 parts, those parts would be too 

 large to pass through them. And these vessels are as 

 large in the brain ot a sparrow, as in that of an ox. 

 Nor is there any difference between the brain of a 

 large animal and a small, but that one contains fac 

 more of these vessels than the other. But the glo- 

 bules of the fluid passing through them are in all ani- 

 mals of the same size. 



The outer part of a turkey's brain is a very clear 

 and transparent oily matter. Innumerable fine blood- 

 vessels are spread through every part of tbis. And 

 if a small part is cut, there ilows out a small globule 

 of pellucid fluid. 



The brain is not absolutely necessary to animal 

 life. Infants have "been born, and lived some time 

 without any. We have an authentic account from. 

 Paris, of a child that survived the birth four days, not 

 only without a brain, bit even a head : instead of 

 which it had a mass of ilesh, somewhat like liver. In. 

 c 5 



