AIR AND VENTILATION 



79 



excretion. The rate of heat loss and of CO 2 excretion depend 

 upon the proportion between the surface of the body and its mass 

 < >r weight. Thus, weight for weight, large animals will produce less 

 carbon dioxide than small ones. 



The following tables of Munk and of Colin show what these 

 investigators found to be the CO 2 excretion during a twenty-four 

 hour period for the various domestic animals.* 



MUNK'S TABLE. 



COLIN'S TABLE. 



Zuntz and Lehmannf give the average CO 2 excretion per hour 

 for a horse weighing about 1000 Ibs., that is a horse of the cab or 

 vanner type, as 3 cubic feet per hour, and this estimate is now 

 considered to be sufficiently accurate for all practical purposes. 

 It has been used for many years as the figure from which to 

 calculate the amount of fresh air required by horses of this size.J 

 It must, however, be fully realised that 3 cubic feet is not a fixed and 

 definite quantity applicable to all sizes of horses and consuming 



* Veterinary Physiology, F. Smith, 1912. 



t Veterinary Physiology, F. Smith, 1912. 



$ Veterinary Hygiene, F. Smith, 3rd Ed., 1905. 



