492 PHYSIOLOGY. 



number of meals and the state of the digestive apparatus. Nitrogen 

 equilibrium can be established by proteoses. 



Phosphorus and thyroid extract increase the elimination of 

 nitrogen. 



In making a nitrogen equilibrium the substitution of carbo- 

 hydrates for fats always acts better on the nitrogen balance than the 

 substitution of fats for carbohydrates. Forced feeding by the 

 addition of proteid increases the storage of proteid material in the 

 body. Hence in wasting diseases of the body large amounts of proteid 

 with some nonnitrogenous food must be given if the proteids and 

 fats are to be increased. 



Chittenden states that if an animal is in a state of nitrogen 

 equilibrium by excessive proteid feeding, if suddenly given a small 

 amount of meat per day it tends to put out nitrogen from its tissues. 

 This tissue loss increases slowly, and eventually the animal is quite 

 likely to establish nitrogen equilibrium at a lower level. 'In other 

 words, there is a strong tendency for the body to pass into a condition 

 of nitrogen balance under different conditions of proteid feeding. 



When proteid is taken in a body in nitrogen equilibrium, a 

 part goes to the repair of the organized proteid which is breaking 

 down, another part will replace the unorganized proteid which has 

 been catabolized, whilst the remainder remains in the tissues as 

 unorganized proteid to be used. There is no reason to think that any 

 proteid is stored in the shape of extractives. 



In the retention of proteid in a surplus of proteid diet, in the 

 adult, there is here an increase in volume of the individual cells of 

 proteid and not an increase in their number. This increase of proteid 

 in the body from a surplus of proteid does not remain when the person 

 returns to his usual diet. 



Alcohol can be substituted for equivalent quantities of carbo- 

 hydrates or fats; that is, can protect them from oxidation. The 

 utilization of the different foodstuffs is not affected by alcohol. 

 Alcohol spares proteid less than carbohydrates when both are given 

 in iso-dynamic quantities, but we do not use alcohol to spare the 

 proteid but the fat of the body. 



When the nitrogen excreted is at constant level and more water 

 is drunk, if diuresis ensues more urinary nitrogen is excreted. Here 

 the nitrogen in the urine is increased because the tissues are more 

 thoroughly washed out. It is a flushing of the nitrogenous end- 

 products and not an unusual breaking up of proteid. The lessening 

 or withdrawal of water did not cause an increase in the consumption of 



