s 
370 CO, Capacity of Blood: IV 
Evidently beyond the critical point the processes causing low- 
ering of the CO, capacity and other ill effects are not reversible. 
Perhaps at these low levels a true acidosis due to tissue asphyxia 
resulting from failing circulation sets in, as suggested some years 
ago in papers on this general subject from this laboratory.* 
The matter is particularly interesting now in view of the fact 
that Porter® has recently reported beneficial results by causing 
wounded soldiers in shock to breathe CO,. In the light of our 
observations we should expect this treatment to hasten the re- 
covery of those cases whose CO, capacity was still above the 
critical level and who would therefore in all probability have re- 
covered slowly without treatment, but to be only a means of 
temporarily prolonging life in cases in which the CO, capacity 
had already sunk below, the critical level. 
In this connection we may mention the fact that some years ago one of 
us had an opportunity to observe and treat in this way a case of shock. 
The case was that of a boy who had been run over by a railroad train. 
One of his feet had been cut off and the other badly mangled. Apparently 
there had been no considerable hemorrhage. Apparently also there was, in 
accord with our correspondent quoted in Paper III, at no time agonizing 
pain. Nevertheless, even when he first came under observation within 
an hour after the accident the character of the breathing was such as to 
indicate a distinct tendency toward apnea. In the course of the next 
few hours during the night there was Cheyne-Stokes breathing. Next 
morning he was at the point of death at about 9 o’clock, respiration hav- 
ing reached the stage of asphyxial inspiratory gasps. CO. gas was ad- 
ministered by holding an inverted glass funnel connected with a tank 
of CO; above his nose. Under such inhalation respiration was restored 
to a form strikingly like that of normal sleep. There was.a marked im- 
provement in the color of the skin and lips and in other vital signs. The 
treatment was continued for 8 or 9 hours and certainly prolonged life 
fully to this extent. Nevertheless the circulation gradually failed and 
death followed. | d 
‘Henderson, Y., Am. J. Physiol., 1908, xxi, 126; 1908-09, xxili, 345; 
1909, xxiv, 66; 1909-10, xxv, 310, 385. Henderson, Y., and Scarbrough, 
M. MeR., ibid., 1910, xxvi, 260. Henderson, ibid., 1910-11, xxvii, 152. 
> Porter, W. T., Boston Med. and Surg. J., 1917, elxxvii, 326. 
