CHAPTER VI. 



THE INFLUENCE OF CHEMICAL FACTORS UPON THE RESPIRATORY 



EXCHANGE. 



The Influence of Various Drugs. 



IN the present section we have to consider the influence of certain 

 drugs which have been shown or are supposed to act on the respiratory 

 exchange. The fundamental problem in this case as in others is to 

 distinguish between such substances which will influence the oxidative 

 energy of the tissues and others which, though they may influence the 

 respiratory exchange, do so by modifying the functional activity of 

 one or more organs. In certain cases a direct influence upon the 

 basal metabolism is easy enough to establish, while in others the 

 nature of the effect is very doubtful. 



THE INFLUENCE OF DRUGS UPON OXIDATIONS IN SINGLE CELLS. 



In "Ergebnisse der Physiologic," 1914, Warburg has given an ex- 

 tremely valuable account of the investigations undertaken by himself 

 and his collaborators on the influence of a large number of substances 

 upon the oxidations in single cells. Though the greater part of his 

 work is outside the scope of the present monograph, it seems desirable 

 here to summarize some of his results as a basis for comparisons with 

 the effects of the same classes of substances upon entire organisms. 



Warburg divides the substances which may influence the oxida- 

 tions in animal cells into two groups : (i) substances which are soluble 

 in lipoids, and (2) lipoid-insoluble substances. 



Substances belonging to the former group will always penetrate 

 into animal cells and become dissolved in the " protoplasm ". The 

 effect of any one of these substances upon the oxidations in different 

 cells is qualitatively and quantitatively nearly the same, and substances 

 which are chemically related show analogous effects. 



Substances belonging to the second group (salts, sugars, amino 

 acids) do not behave uniformly with regard to different cells. Some 

 of them may penetrate into certain cells but remain excluded from 

 others, some may influence the rate of oxidations in certain cases, and 

 leave it intact in others. 



66 



