92 Parts of the Body. [Book IX. 



the limbs of their parents. So endlefs indeed are thefe 

 differences, that there is perhaps no one circumftance 



of ftructure or function common to all animals. 



But let us return from thefe extenfive profpects to the 

 confideration of the ftructure of our own fpecies. 



Before we proceed, however, to confider the ftruc- 

 ture of the body, it will be proper to premife a few 

 very brief definitions' of the moft remarkable parts of 

 which it confifts. 



Bones are hard fubftances, which form the bafis of 

 the body. 



Cartilages are firm, fmooth, elaftic bodies, which 

 cover the ends of the bones. 



Mufcles are contractile organs, which are attached 

 to bones, and perform the motions of the body. 



Tendons are tough cords, by means of which 

 mufcles are attached to bones. 



Ligaments are ftrong fibres or membranes, which 

 connect bones to each other. 



Blood- veffels are membranous flexible tubes, which 

 convey the blood to and from the heart. 



Lymphatics are tranfparent tubes, which perform 

 abforption. 



Nerves are white cords connected with the brain, 

 and are die inftruments of fenfation and voluntary mo- 

 tion. 



Glands are organic mafles, deftined for die purpofe 

 of fecretion. 



