THEORETICAL CONSIDERATIONS. 53 



from the fuel consumed, which caloric is subsequently trans- 

 formed into power in the receiving receptacle. From this it is 

 concluded that it is mainly from the carbohydrates that heat is 

 obtained, and the resulting force is only 20 per cent, of the total 

 caloric, which results are however superior to the very best 

 mechanical appliances. This is only theory and does not agree 

 with the facts of the case. If the forces of the body represented 

 a simple transformation of animal heat, it would be possible to 

 keep on working night and day without the least sensation 

 of fatigue. 



If there is greater heat produced during work than in rest, 

 this is compensated by the increased perspiration which estab- 

 lishes an equilibrium. Some years since it was declared that 

 when, feeding animals during excessive work, their rations must 

 contain considerable protein, and a comparatively small amount 

 of carbohydrates. The function of protein is not to produce 

 power, but it is essential for muscular activity. 



Recent experiments, on the other hand, show that carbo- 

 hydrates, such as sugar, actually mean strength. There can 

 be no doubt that animals store up a certain amount of power in 

 various forms. Max Ru'bner has demonstrated that dynamic 

 equivalents of nutrients are almost exactly equal to their 

 caloric equivalents. It is, however, to Stohmann that the 

 credit must be given of this interesting discovery. It has been 

 demonstrated that 100 parts of fat have the following equivalents: 



EQUIVALENTS FOR 100 PARTS OF FAT. 



