SECTION i: CAKDIFF, 1920. 



ADDRESS 



TO THE 



PHYSIOLOGICAL SECTION 



BY 



J. BARCROFT, C.B.E., M.A., F.R.S., 



PRESIDENT OF THE SECTION. 



Pkominent among the pathological conditions which claimed attention 

 during the war was that of insufficient oxygen supply to the tissues, or 

 anoxaemia. For this there were several reasons; on the one hand, 

 anoxaemia clearly was a factor to be considered in the elucidation of such 

 conditions as axe induced by gas-poisoning, shock, &c. On the other 

 hand, knowledge had just reached the point at which it was possible to 

 discuss anoxaemia on a new level. It is not my object in the present 

 address to give any account of war-physiology — the war has passed, and 

 I, for one, have no wish to revive its memories, but anoxaemia remains, 

 and, as it is a factor scarcely less important in peace than in war 

 pathology, I think I shall not do wrong in devoting an hour to its 

 consideration. 



The object of my address, therefore, will be to inquire, and, if pos- 

 sible to state, where we stand; to sift, if I can, the knowledge from 

 the half -knowledge ; to separate what is ascertained as the result of 

 unimpeachable experiment from what is but guessed on the most likely 

 hypothesis. In war it was often necessary to act on defective informa- 

 tion, because action was necessary and defective information was the 

 best that was to be had. In this, as in many other fields of know- 

 ledge, the whole subject should be reviewed, the hypotheses tested ex- 

 perimentally, and the gaps filled in. The sentence which lives in my 

 mind as embodying the problem of anoxaemia comes from the pen of 

 one who has given more concentrated thought to the subject than per- 

 haps any other worker — Dr. J. S. Haldane.^ It runs, ' Anoxaemia not 

 only stops the machine but vreecks the machinery.' This phrase puts 

 the matter so clearly that I shall commence by an inquiry as to the 

 limits within which it is true. 



Anything like complete anoxaemia stops the machine with almost 

 incredible rapidity. It is true that the breath can be held for a con- 

 siderable time, but it must be borne in mind tha,t the lungs have a 

 volume of about three litres at any moment, that they normally 

 contain about half a litre of oxygen, and that this will suffice for the 

 body at rest for upwards of two minutes. But get rid of the residual 

 oxygen from the lungs only to the very imperfect extent which is 



* See References, page 168. 



