!)4 



A Manual of Veterinary Physiology. 



these observers absorbed more oxygen and gave out more 

 carbonic acid than the English cavalry horses with which I 

 worked, and according to their experiments the amount of 

 carbon produced by a horse in 24 hours is about 25.'. ozs. 

 Here is a table of my own, showing the respiratory changes 

 for one hour in a horse during perfect repose : 



Cubic feet of air per hour .... 74-25 



Carbonic acid expired per hour in cubic feet- - TG3 



Oxygen absorbed per hour in cubic feet - - 1-13 



Undetermined gases - -429 



Respiratory quotient ----- -69 



There are certain conditions which influence the produc- 

 tion of carbonic acid, of which the most important is mus- 

 cular work. As the result of increased muscular activity 

 the production of carbonic acid is considerably increased. 

 This increase is carried away by the blood-stream, and got 

 rid of at the lungs as previously explained. It is evident 

 that the more severe the work, or the greater the strain 

 thrown on the muscles, the greater the amount of CO. pro- 

 duced. I have endeavoured to ascertain what this amount 

 is for each pace of the horse, and the results of a large 

 number of observations are embodied in the following 

 table : 



The above table does not agree with the elaborate re- 

 searches of Zuntz and Lehmann, but, then, the work per- 

 formed by their horses was executed on a revolving platform, 

 whereas work of a normal kind was performed by tho 



