VENTILATION. 
629 
of ventilation, that still much remained to be done; and that 
as yet no uniform plan had been suggested which would 
remedy existing defects, and secure in all cases, and under 
all circumstances, an aggregate supply of pure air. 
Subsequent reflection has convinced me that no subject 
has a more intimate relation to animal life than this, nor is 
there one connected with the noble principles of our science 
that requires more consideration on our part of its princi¬ 
ples, or careful discussion of its details, than ventilation. 
I have therefore selected it as the subject for our conside¬ 
ration this evening, in the hope that our discussion may tend 
to confirm the adoption of some uniform system upon which 
it should be established. 
Proper ventilation, as applied to stables, consists in the 
introduction of a sufficient quantity of pure air to keep up 
a due supply of oxygen which has become absorbed, and in 
the removal of that portion which has become vitiated or 
destroyed. To be perfect, it must be conducted upon strict 
scientific principles, formed by careful calculations as to the 
demand ; the supply so regulated and applied in construc¬ 
tion, that it can be tested with ease and accuracy. 
Hence, the first important point for our consideration con¬ 
sists in ascertaining what is the quantity of air vitiated by a 
single horse, and what quantity will he require in a given 
time to keep him in a heaithy condition. 
To do this correctly 1 shall have to trespass on your atten¬ 
tion for a short time, whilst I endeavour to give you an esti¬ 
mate of these quantities drawn from the recent investiga¬ 
tions of human physiologists on this subject. 
An ordinary healthy atmosphere has been stated to consist 
of the following constituents : 
Oxygen 
197 
Nitrogen 
. 78-8 
Aqueous vapour . 
. 1-4 
Carbonic acid . 
. 01 
100-0 
Any animal shut up in a close stable injures the purity of 
this air in those very matters which act injuriously to his 
health. 
1st. He withdraws oxygen by the process of respiration, 
and thus diminishes its proportionate quantity. 
2nd. He replaces the oxygen by an equivalent of carbonic 
acid, and thus increases the amount of that gas. 
3rd. By the natural process of exhalation from the lungs 
and skin, he increases the proportion of water in the air. 
