EXCHANGE OF MATERIAL. 467 



FOKKER and J. MUNK after the administration of small amounts of 

 alcohol to dogs found a diminished, and after large amounts an 

 increased, metabolism of proteids. 



Many observations have been made in regard to the extent of 

 exchange of gas after taking alcohol. BOECK and BAUER observed 

 in dogs after giving small amounts of alcohol that the consumption 

 of oxygen as well as the elimination of carbon dioxide was increased. 

 BODLANDER found in rabbits and dogs a decrease in the consump- 

 tion of oxygen and the elimination of carbon dioxide, while WOL- 

 FERS found an increased consumption of oxygen in rabbits. In an 

 investigation on the human body ZUNTZ and BERDEZ, and also 

 GEPPERT, observed no essential change in the respiratory exchange 

 of gas after small, non-intoxicating doses of alcohol. As alcohol is 

 in greatest part burnt up in the body and the exchange of gas is 

 nevertheless not essentially raised, it seems as if the alcohol dimin- 

 ishes the combustion of other bodies and thereby has a sparing 

 value. This value may still, if it really has such an action, be of 

 essential importance only in certain cases, as large quantities of 

 alcohol taken at once or the continued use of smaller quantities has 

 injurious action on the organism. Alcohol may therefore be con- 

 sidered as a nutritive body in exceptional cases only, and it other- 

 wise must be considered as an article of luxury. 



Coffee and tea have no positively proved action on the exchange 

 of material, and their importance lies chiefly in their action upon 

 the nervous system. 



IV. The Dependence of the Exchange of Material on 

 Other Conditions. 



Rest and Work. According to LIEBIG, muscular activity is con- 

 nected with an increased metabolism of proteids, but, as has been 

 mentioned on page 267, the investigations of others, especially VOIT 

 on dogs, and of PETTENKOFER and VOIT on man, show that the 

 total elimination of nitrogen during activity or as a result of the 

 same is not mentionably increased. It is indeed true that certain 

 investigators have observed an increased elimination of nitrogen in 

 special cases; but this increase has been explained in other ways. 



Work may, for instance, when it is connected with violent 



