Digestion, Respiration and Calorimetry. 35 



From these data we learn that in twenty-four hours the steer took 

 into the blood by way of the lungs 16 pounds of oxygen, and 

 into the alimentary tract 27.8 pounds of dry matter and 128 

 pounds of water, or 171.8 pounds in all. 



57. Waste products. The second division of the table treats 

 of production and waste. Let us first consider the waste by the 

 steer for the day during which the study was conducted. The 

 loss to the body through the several channels was as follows: 



Pounds. 



Passed off as solid excrement 89.4 



Passed off as urine 30.6 



Passed off as respiration products 49.5 



Total waste 'from body 169.5 



This shows that there passed from the steer as solid excrement 

 89.4 pounds, of urine 30.6 pounds, while from the lungs there 

 were given off 49.5 pounds of waste products, somewhat more 

 than one-half of which was water, and a little less than half car- 

 bonic acid. The total outgo from the body for the day under 

 study, was as shown above, 169.5 pounds. 



The decomposition of nitrogenous substances in the body is 

 calculated from the quantity of nitrogen in the urine. As pro- 

 tein contains 16 per cent, nitrogen on the average, the quantity 

 of protein corresponding to the nitrogen in the urine is found by 

 multiplying by iff-, or by 6.25. The table shows that there were 

 .170 kilograms of nitrogen in the urine of the ox. Multiplying 

 this by 6.25, there results 1.062 kilograms or 2.38 pounds. This 

 sum measures both the quantity of nitrogenous nutrients taken 

 into the body from, the food, and the body tissues which were 

 broken down and left the body as waste during the day of the trial. 



58. Flesh production. From the above we have the following 

 in relation to the income and outgo of the body of the steer for 

 one day: 



Pounds. 



Total substance passing into the body 171.8 



Total waste leaving the body 169.5 



Amount retained in the body 2.3 



