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VETERINARY PHYSIOLOGY 



2, In groups of viuscles in the body. — When the 

 work done by groups of muscles within the body has to be 

 studied, some form of work-measurer or ergometer must be 

 devised. A horse may be made to walk upon a platform 

 which moves against a known resistance, or the pull exerted 

 may be measured by means of a dynamometer, a simple form 



Fig. 128. — Graph to show the effect of increasing the pace of walking upon 

 the expenditure of energy measured by the oxygen consumed and 

 carbon dioxide given off. (Briggs. ) 



of which would be a spring balance inserted between the 



horse and the object pulled. By these means the capacity 



of the horse for work (p. 252) has been determined 

 experimentally. 



7. Heat Production in Muscle. 



In muscle, as in a steam-engine or any other machine, by 

 no means the whole of the energy is used for the production 

 of mechanical work. Much of the energy is lost as heat. 

 But while this is an actual loss in the steam-engine, the pro- 



