28 VENTILATION. 



cific conditions and then solely for their quieting and resting 

 effects, such as is desired for the overtired hunter and race 

 horse during the short season of their violent exertion. The 

 absence of light in any part of the stable promotes the action 

 of dampness, filth and disease. 



VENTILATION. 



The value of fresh air in the stable is commensurate with 

 the importance given to its influence on the human system. 

 The organic life of a horse is influenced, sometimes imper- 

 ceptibly, at other times markedly, by the presence or partial 

 absence of fresh air. The effect of the atmosphere on the 

 health of the horse is of such importance that some explicit 

 explanation of its influence is pertinent in considering the 

 subject of ventilation : 



The atmosphere is at one and the same time a purveyor of food to the 

 system and a gatherer of waste particles. At each beat of the heart, blood is 

 pumped into the capillary vessels which cover the cells of the lungs. While 

 passing through these membranous sacs it is exposed to the action of the air 

 and is converted from venous into arterial blood by the absorption of oxygen 

 and the giving up of carbonic acid gas. The solid waste substances that 

 the blood gathers in its passage through the vascular structure are removed by 

 excretion. An additional and equally important function of the atmosphere 

 is to furnish heat to the body. This warmth is produced by the chemical 

 combustion of the oxygen of the air uniting with the carbon of the tissues. 

 By the action of impure air the corpuscles are less highly vitalized owing to 

 its being heavily charged with carbonic acid gas, hence it renders the blood 

 less nourishing, less purified, and reduces the amount of combustion. Vi- 

 tiated air by thus impoverishing the blood, poisoning the system and lowering 

 the temperature of the body, induces a state of unhealthiness and prepares a 

 fertile soil for the reception of every form of disease germ. 



The means of introducing fresh air into the stable should 

 be so judiciously arranged that the cold air will become tern- 



