DISEASES OF RESPIRATORY PASSAGES AND ORGANS. 



S9 



twelve per minute, varying, however, according to the tempera- 

 ment of the animal and the condition he may be in at the time 

 of making the observation ; while in horses the respirations art' 

 more frequent, varying in health, and when at rest, from fourteen 

 to twenty-five; yet, under excitement and disease, they sometin es 

 BTjmber over one hundred. 



\ N - 



TBB C0HTEKT8 Or TBI TBOKAX. 



■DI.AXATIOH.— rtg. I, Trachae ; 2, BIfnrcfttion of the carotid artery; 3. Internal carotid mtimfl 

 « t, Anterior lobes of the Innga: 5 5 Po«terior lobos of the Inngg; 6, The heart; 7. Ooronut 

 •rtery ; 8, Cartilages of the false ribs ; 9, The diaphragm. 



When an animal is located in a pure atmosphere, and the 

 lungs are in gocxl working condhion, all the impurities contained 

 in venous blood are brought into the presence of oxygen through 

 the lining membrane of the air-cells, and thus a change in the 

 color and character of tlie blood is immediately effected. In the 

 fljTbt place, the venous blood, as it appeared before having teen 

 imhmitted to the action of the atmosphere, was of a dark porpl« 



