468 PHYSIOLOGICAL CHEMISTRY. 



movements of the body, easily cause dyspnoea, and this last may, as 

 FRANKEL has shown, since diminution of the oxygen supply in- 

 creases the proteid metabolism, cause an increase in the elimination 

 of nitrogen. In other series of experiments the quantity of carbo- 

 hydrates and fats in the food was not sufficient; the supply of fat 

 in the body was decreased thereby, and the destruction of proteid s 

 was also correspondingly increased. Work may also increase the 

 appetite, and an increase in the elimination of nitrogen may be 

 caused by the greater quantity of proteids taken. According to 

 the generally-accepted views, muscular activity has hardly any in- 

 fluence on the metabolism of proteids. 



On the contrary, it has a very considerable influence on the 

 metabolism of non-nitrogenized bodies and as a measure of the 

 extent of the metabolism on the elimination of carbon dioxide 

 and the consumption of oxygen. This action, which was first 

 observed by LAVOISIER, has recently been confirmed by many in- 

 vestigators. PETTENKOFER and VOIT have made investigations as 

 to the metabolism of the nitrogen ized as well as of the non- 

 nitrogenized bodies during rest and work, partly while fasting 

 and partly on a mixed diet. The experiments were made on a 

 full-grown man weighing 70 kilos. The results are contained in 

 the following table : 



TABLE XIII. 



Consumption of 



, ---- ----- , Water 



Proteids. Fat. Carbohydrates. CO 2 eliminated. O consumed, expired. 



tfoot^r j Rest.. 78 215 ... 716 761 889 



casting... - Work 75 380 1187 



TIT j ,,- ,j Rest.. 137 65 352 912 831 828 



et \ Work 137 173 352 1209 980 1412 



The work in this case had no influence on the destruction of 

 proteids, while the consumption of non-nitrogenized bodies and 

 the elimination of water by the skin and lungs was considerably 

 increased. 



The question of the exchange of material in sleep and waking 

 stands in close relationship to the exchange of material in rest and 

 activity. According to PETTENKOFER and VOIT, the metabolism of 

 proteids is not constantly influenced by these two different condi- 

 tions; on the other hand, the production of carbon dioxide is 

 habitually greater during the day than in the night. If excessive 



