218 NATURAL THEOLOGY, 



be scattered over the surface, like warts or pim- 

 ples.« 



3. All the great cavities of the body are en- 

 closed by membranes, except the skull. Why 

 should not the brain be content with the same 

 covering as that which serves for the other prin- 

 cipal organs of the body ? The heart, the lungs, 

 the liver, the stomach, the bowels, have all soft 

 integuments, and nothing else. The muscular coats 

 are all soft and membranous. I can see a reason 

 for this distinction in the final cause, but in no 

 other. The importance of the brain to life, (which 

 experience proves to be immediate.) and the ex- 

 treme tenderness of its substance, make a solid 

 case more necessary for it, than for any other 

 part; and such a case the hardness of the skull 

 supplies.^ AVhen the smallest portion of this 



^^ The human nail is calculated to support the cushion of the 

 extremity of the finger, and is important to us in grasping or hold- 

 ing any thing; but more so still in sustaining that cushion as the 

 chief organ of touch. There are other parts of the body which 

 have exquisite sensibility, yet they are not provided so as to give 

 us that information of the condition of matter which we have 

 through the finger, and in a lesser degree through the whole in- 

 ner surface of the hand. We easily feel, for example, the pulsa- 

 tion of the artery at the wrist, through the combination of the 

 sensibihty of the nerve of touch with the elastic cushion of the 

 finger. The best proof of the use of the elastic cushion is this : 

 Although the tip of the tongue feels so exquisitely that the pre- 

 sence of a hair of wool troubles us, yet if we apply it to the pulse 

 we shall not be sensible of the beat. 



^ There is a note upon the form of the skull in the Appendix, 

 which may interest the reader. 



