32 HEAD. 



r 



are previously divided into a number of little branch- 

 es, which, by multiplying the channels, diminishes the 

 rush of the stream. 



B. I shall never feel a throb in the head again, 

 after any violent exertion, without thinking of these 

 admirable securities. 



A. The principal vessels which bring the blood 

 back from the brain are also a curiosity of contri- 

 vance. What is extraordinary, they differ from all 

 other veins in the body which are used for returning 

 the blood to the heart. It is plain, the blood dught 

 to have the freest and easiest return possible from the 

 brain. Any obstruction would be followed by the 

 most serious consequences immediately. " There- 

 fore, it is one of those particulars which powerfully 

 affect a contemplative mind, as proofs of a designing 

 intelligence," says a late eminent writer, (Arnott on 

 Physics), " that the chief channels which return the 

 blood from the head, are not common compressible 

 veins, (the common veins are skinny or membranous 

 tubes, easily pressed together), but they are what 

 anatomists call sinuses, or grooves in the bone itself, 

 with exceedingly strong membranous coverings, sup- 

 ported so powerfully, that the channels become in 

 strength little inferior to complete channels of bone." 



T. There are many varieties adapted to the na- 

 ture and circumstances of different animals. The 

 head most nearly resembling the human is that of the 

 monkey ; but there are several respects in which the 

 similitude fails, as may be seen in treatises upon 

 comparative anatomy 



