36 Hounds 



The cavity of the chest is lined by a delicate 

 serous membrane, which is reflected over the surface 

 of the lungs and midriff. This is the pleural mem- 

 brane, and its use is to enable free gliding move- 

 ments of the lungs, its surface always being slightly 

 moistened for this purpose. 



In appearance the lungs are soft spongy organs, 

 pale red in colour and divided into several lobes on 

 the right and left side. Microscopic examination 

 shows the lungs to be composed of numberless 

 minute air-sacs or spaces — the alveoli — each space 

 being surrounded by a plexus of fine blood- 

 vessels — the capillaries — which bring the blood 

 in contact with the air (oxygen) within the air- 

 cells. 



The respiratory act is divisible into two portions, 

 viz., inspiration and expiration, or the taking in of 

 air and giving it out. 



Air ought to enter the lungs uncontaminated, but 

 this cannot be the case in an atmosphere polluted 

 with offensive products, such as a kennel where the 

 excretions are allowed to remain too long, under- 

 going decomposition. Free ventilation of the kennel 

 is indispensable. 



The number of respirations per minute varies 

 greatly, exercise, heat, etc., all influencing the 

 respiratory movements. Unlike the horse, the dog 

 breathes largely through its mouth, as evidenced 



