NO. 1 AIR AND TUBERCULOSIS — HINSDALE 29 



cent ; but Paul Bert ' also showed that too much oxygen was equally 

 prejudicial to life and, indeed, poisonous, animals dying in a super- 

 oxygenated atmosphere as soon as their blood contains one-third 

 more than the normal ratio of oxygen, because in such an atmos- 

 phere the hemoglobin of the red blood corpuscles is saturated with 

 oxygen — a fact which never occurs under normal conditions — and a 

 proportion of this gas then dissolves in the serum of the blood 

 Here lies the danger, for the tissues cannot withstand the presence 

 of free, uncombined oxygen and death follows. The question imme- 

 diately arises: Why do the tissues require combined oxygen and 

 why does free oxygen kill them ? No one knows. Henry de Varigny, 

 who deals with this subject with reference to aerobic and anaerobic 

 organisms deals with this curious fact and acknowledges our limited 

 knowledge on this point. He states, however, that while a certain 

 increase in the ratio of oxygen results in death, lesser increases of 

 a temporary character may be beneficial. Every poison kills, doubt- 

 less, but there are doses which not only do not kill, but even confer 

 benefit and improve health. 



Lorrain Smith has shown that oxygen at the tension of the atmos- 

 pb.ere stimulates the lung-cells to active absorption; at a higher 

 tension it acts as an irritant, or pathologic stimulant, and produces 

 inflammation.'* 



As far as the respiratory processes are concerned the respiration 

 of pure oxygen takes place without disturbing them for even in an 

 atmosphere of pure oxygen animals breathe as though they were 

 respiring normal atmospheric air."* 



Sir Humphrey Davy believed that when pure oxygen was inspired 

 there is no more chemical change induced than occurs when atmos- 

 pheric air is breathed; in other words, let the vital actions be a 

 constant quantity, the addition of oxygen to the inspired air does 

 not materially increase vital transformation. Fifty years ago there 

 was great confusion in the minds of otherwise intelligent observers 

 and false reasoning led them into grave errors. Those who, like 

 Beddoes, believed that there was too much oxygen in the system held 

 that the inhalation of air containing carbonic acid was the proper 

 plan of treatment and this theory of hyper-oxidation was revived 



^ Paul Bert: La Pression Barometrique, 1878. 



See also monograph by F. G. Benedict quoted on page 31. 

 - Lorrain Smith, in Journal of Physiology, 1899, Vol. 24, p. IQ- 

 ^ An American Text Book of Physiology, Vol. i. 



