72 



As will be seen, the amount of total nutrients required increases with 

 the increased speed; furthermore, a greater amount is required in 

 climbing an incline than for forward progression on a level. In 

 descending a gentle incline a much smaller amount of nutrients is 

 required than in climbing the same incline, and as compared with the 

 motion of forward progression there is also a saving in the amount of 

 nutrients needed. In general, it was found that the energy expended 

 was less than in traveling on a level, provided the incline was less than 

 5° 45'. At this point it was equal to the amount expended in travel- 

 ing on a level. If the incline was greater, energy was required to 

 keep the body from descending too rapidly and the expenditure was 

 greater than on a level. The different values given in the above table 

 for the nutrients required for the performance of different kinds of 

 work are obtained by taking the sum of the requirements for the dif- 

 ferent components into which the work can be resolved; thus, in trot- 

 ting 1 kilometer (3,281 feet) with a load of 75 kilograms (165 pounds) 

 the total work consists in that expended for forward progression and 

 for moving the load over the distance covered. 



An example of the way in which the value of a ration was calculated 

 by Zuntz follows: 



If a farm horse weighing 500 kilograms (1,100 pounds) walks eight 

 hours drawing a load at a speed of 4 kilometers (2.5 miles) per hour, 

 the work performed and the total available nutrients required would 



be as follows: 



Table 11. — Total nutrients required for work. 



32 kilometers (20 miles') forward progression 



2,144,000 kilogrammeters (15,436,800 foot-pounds) mechanical work 

 Maintenance (exclusive of labor of digestion ) 



Total 



Total nutrients. 



Pounds. 

 2.654 

 8.975 

 2. 425 



14. 064 • 



The ration selected consisted of 3 kilograms (6.6 pounds) hay, 1.5 

 kilograms (3.3 pounds) straw, 2 kilograms (4.4 pounds) Held beans, and 

 a sufficient amount of oats to l)ring the total nutrients of the ration up 

 to the required amount. The nutrients furnished by the hay, straw, 

 and held beans would be as follows: 



Table 12. — Total nutrients furnished by tentative ration. 



Total nutrients, 



3 kilograms (6.6 pounds) of hay, requiring per kilogram (2.2 pounds) for diges- 

 tion 627 grams (1.38 pounds) ;•■•/■•%•- 



1.5 kilograms (3.3 pounds of straw, requiring per kilogram (2.2 pounds) for diges- 

 tion 445 grams (0.98 pound) V • %"• 



2 kilograms (4.4 pounds) of beans, requiring per kilogram (2.2 pounds) for diges- 

 tion 222 grams (4.9 pounds) ; 



Total, 1,294 grams (2.85 pound.s) 



+3.505 



