100 PHYSIOLOGY. 



wound gapes open, owing to the two parts receding. The 

 cartilages of the ribs are highly elastic, and this facilitates 

 much the function of respiration. The same is true of the 

 substance of the lungs themselves. The cartilages between 

 the bones and the spine are highly elastic. The loss of this 

 elasticity makes a difference of an inch or more between the 

 height of a man in the morning and at evening. It is 

 not unusual for a very tall person to lose an inch in height 

 by dancing all the evening. x During sleep, the force of 

 elasticity restores these cartilages to their usual dimen- 

 sions. 



27. The elasticity *of the arteries contributes much to the 

 circulation of the blood. The blood as it is forced into these 

 vessels, is constantly reacted upon, by their elastic coats, 

 and in this way driven along towards their termination in 

 the capillary vessels. The same power assists in circulating 

 the lymph and chyle in the vessels which contain them. It 

 is the last function that ^ceases to act, and it is not wholly 

 destroyed even at death./ 



28 ^Flexibility and extensibility are properties existing in 

 various degrees in different parts of the body. The liga- 

 ments, or little bands, which tie together the bones, are more 

 flexible than any other part. By observing the astonishing 

 feats of the rope-dancer, we see how flexible these parts are. 

 The tendons which connect muscles with the bones they 

 move, are capable of little, if any extension. If they stretch- 

 ed, when the muscles to which they belong contract, the 

 (imbs would not move, and the moving force would thus be 

 lostj 



29. Imbibition, is another power possessed by living animal 

 bodies. ^.It means the act of drinking in, or taking up fluids, 

 which may be in contact with any part.? For example, if a 

 certain fluid be placed in contact with an animal tissue, it. 

 will penetrate into the latter, as water would into a sponge, 

 and this property is possessed by all the soft tissues to a 

 greater or less extent. All the serous membranes absorb 



