RESPIRATION. 163 



animal is revived into buoyancy and energy. In these ani- 

 mals, while respiration is low, life is low ; and, on the con- 

 trary, while respiration is active, life is in the same condition. 

 A similar relation between the amount of respiration and 

 the fulness and activity of life is shown in the various races 

 of animals. " The development of their locomotive powers, 

 and the degree of heat maintained in their systems, will be 

 found peculiarly connected with the activity of respiration." * 

 Those which breathe most are the most vigorous, lively, and 

 active, while those which breathe least are the most sluggish, 

 stupid, and feeble. 



377. The same law holds good for the different individu- 

 als of any class, as well as for the various races of animals. 

 There is a manifest connection between any man's fulness 

 and energy of life and the development and free use of his 

 respiratory organs. Wherever the lungs are imperfect, or 

 air insufficiently supplied, there is a lower life, a feebler 

 power of locomotion, less muscular energy, a duller nervous 

 system, a more inactive brain. 



378. These effects are not always noticed and referred to 

 their true causes, yet they are none the less certain. In 

 persons suffering from consumption, the lungs are more or 

 less rilled with tubercles and abscesses ; the air-vessels are, to 

 the same extent, closed, so that the air cannot penetrate 

 them, and reach the blood, to purify it. These men are not 

 well nourished, for want of pure blood, and therefore they 

 waste away ; their muscles grow thin and weak, arid their 

 buoyancy of life is extinguished. Their lungs become filled 

 more and more as the disease progresses ; and, at last, when 

 respiration can no longer be carried on with sufficient power 

 to effect its due purposes, they sink in death. 



379. Whatever may be the cause that prevents the lungs 

 from receiving a full and requisite quantity of air, the result 

 is the same a lower degree of life. Whether the chest be 

 originally small in proportion to the size- of the body, or 



* Carpenter's Comparative Physiology. 



