132 PRINCIPLES AND PRACTICE OF MILK HYGIENE 



ing effect upon the animal organism. It decreases the 

 working capacity of the muscles and lowers the vaso- 

 motor tone. It also causes a congestion of the nasal 

 mucous membrane, rendering the animal more suscep- 

 tible to respiratory infection. There is also reason to 

 believe that metabolism is depressed. A moderately cool 

 and moderately dry air in motion is the most healthful 

 atmosphere for animal life. 



Ventilation. The best system of ventilation for dairy stables 

 is the one devised by the late Prof. F. H. King. Like other 

 systems, it has inlets for the admission of fresh air and outlets 



FIG. 9. Showing on the left how an inlet can be placed in a wall already constructed; 

 on the right, how an inlet can be put in a wall being built; and in the centre, an outlet shaft 

 with two openings one just under the ceiling and one a foot above the floor. 



for the removal of impure air, but it has two features which are 

 peculiar to it. The inlet flues are bent at a right angle, and 

 the outside opening is lower than the inner one, the purpose 

 being to prevent the escape of air from the stable through the 

 inlets. The outlet flues are built from the floor up and have 

 an opening near the floor as well as one near the ceiling, thus 

 providing a means of drawing air not only from the upper 



