RES P IRA TION 609 



in the heart, under the action of adrenaline, great increase both in oxygen con- 

 sumption and in carbon dioxide output occurred, but that the two processes do 

 not coincide in time. The oxygen intake reaches its maximum during the first 

 few minutes after the drug is given, while the output of carbon dioxide reaches 

 its maximum some time later, after the oxygen intake has begun to diminish 

 again. The respiratory quotient is thus first lowered and then raised before 

 returning to normal, but the mean value is unaltered. The explanation suggested 

 is that a definite time is required for the chemical reactions which occur in the 

 intermediate stages of oxidation, so that, if there is an increase in the rate of 

 oxidation generally, the amount of oxygen consumed alters at once, while that 

 of the carbon dioxide output attains its new level more slowly. This view is 

 confirmed by the fact that, if adrenaline is continually added, the mean respiratory 

 quotient during the administration becomes constant, but at a lower level than 

 before the adrenaline was given. This can be seen in detail in the consideration 

 given on p. 456 of the paper. It is merely necessary to remember that the 

 carbon dioxide given out in a particular period does not correspond to the oxygen 

 used in that period, but to that of an earlier period. 



Certain interesting experiments on the growth of yeast by Horace Brown (1914) appear, at 

 first sight, to show that there is, in this case, a storage of oxygen. If yeast be placed into a 

 culture solution, which has been saturated with oxygen at its tension in air by shaking with 

 air, the oxygen is removed rapidly and serves for subsequent combustion purposes by the 

 yeast cells which have taken it up. In interpreting this result, it should be remembered 

 that the amount of oxygen present in the solution was only 0'559 c.c. per cent., and also 

 that (p. 212) it was found impossible to increase the "oxygen charge" of normal yeast, 

 which had been washed in contact with air, by submitting it to more extensive aeration. The 

 possibility of peroxides may be taken into account here (see the footnote on p. 212 of the 

 paper), and also that of adsorption of oxygen on surfaces in the cell, since the amount taken 

 up was so small. 



The Relation of Oxygen Tension to its Consumption. We find almost invariably 

 that the supply of oxygen is sufficient to meet the requirements of the cell, so that 

 increase of its pressure ( = concentration) does not lead, by mass action, to increased 

 consumption. In the case of the slug, the earthworm, and the mealworm, 

 Thunberg (1905, 2) found, on the contrary, that the consumption of oxygen was, 

 within fairly wide limits, in proportion to its tension. 



NARCOSIS 



Some phenomena and theories of narcosis have been discussed previously 

 (pages 138-140). That of Verworn (1912), according to which the process consists 

 in the inhibition of oxidation, was left until the present chapter. Allied to this 

 view is that of Mansfeld (1909), which attributes the process to an effect on the 

 cell membrane by which access of oxygen is prevented. This blockage is supposed 

 to be due to the diminution of the solubility of oxygen in the lipoid membrane, 

 owing to the presence of the narcotic there ; but, if ordinary solution be meant, 

 it is difficult to reconcile the view with the ordinary laws of solubility. 



Direct evidence exists, moreover, which shows that there is no connection 

 between narcosis and oxidation. Thus Warburg (1910, 2) found that, although 

 the segmentation of the sea urchin's egg was stopped by phenyl-urethane, the 

 consumption of oxygen was not ; a greater concentration of the narcotic, however, 

 stopped the latter also, as would be expected. 



Winterstein (1913) shows that there is no relation between the narcotic action 

 of various substances, and their effect on oxidation. Further, anaerobic worms 

 cau be anaesthetised. In a further paper (1914), it is shown that the spinal cord 

 of the frog, when narcotised by urethane, shows diminished oxidation, but 

 when narcotised by alcohol, the oxidation is increased. The two processes are 

 independent. The fact that nerve centres, after asphyxia, cannot be recovered by 

 oxygen, if alcohol be present, shows that there is some intermediate process 

 between oxidation and excitability, which process is attacked by the narcotic. 



As to what the process actually consists in, certain facts have been given previously, and 

 we may remember that Claude Bernard (1875, p. 143) suggested that the various forms of 



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