ANIMALS. 61 



Thus, in old age, every action of the body is per- 

 formed with labour ; and the cartilages, formerly 

 so supple, will now sooner break than bend. 



" As the cartilages acquire hardness, and unfit 

 the joints for motion, so also that mucous liquor, 

 which is always separated between the joints, and 

 which serves, like oil to a hinge, to give them an 

 easy and ready play, is now grown more scanty. 

 It becomes thicker, and more clammy, more un- 

 lit for answering the purposes of motion ; and 

 from thence, in old age, every joint is not only 

 stiff, but awkward. At every motion, this clam- 

 my liquor is heard to crack ; and it is not with- 

 out the greatest efforts of the muscles that its 

 resistance is overcome. I have seen an old per- 

 son, who never moved a single joint that did not 

 thus give notice of the violence done it." 



The membranes that cover the bones, the joints, 

 and the rest of the body, become, as we grow old, 

 more dense and more dry. Those which sur- 

 round the bones, soon cease to be ductile. The 

 fibres, of which the muscles or flesh is composed, 

 become every day more rigid ; and while to the 

 touch the body seems, as we advance in years, 

 to grow softer, it is, in reality, increasing in hard- 

 ness. It is the skin and not the flesh, that we feel 

 upon such occasions. The fat and flabbiness of 

 that seems to give an appearance of softness, 

 which the flesh itself is very far from having. 

 There are few can doubt this after trying the dif- 

 ference between the flesh of young and old ani- 

 mals. The first is soft and tender, the last is hard 

 and dry. 



