872 STUDIES IN GENERAL PHYSIOLOGY 
tions which are characteristic of living matter.’ If, how- 
ever, oxygen is absent, the chemical changes will be of an 
entirely different character. Compounds may be formed 
which are poisonous for the organism. Araki, for example, 
has shown that when oxygen is lacking considerable amounts 
of lactic acid and sugar appear in the urine. If the oxygen 
supply is normal, these compounds may also be formed from 
glycogen as intermediate products, but they are soon 
oxidized further. To the immediate consequences of lack 
of oxygen are therefore added those which are determined 
through the presence of lactic acid in the body—for ex- 
ample, a diminution in the alkalinity of the blood. The cells 
of the kidney are also altered, as evidenced by the albumi- 
nuria which results when oxygen is lacking.’ 
While there exists a comparatively large number of in- 
vestigations concerning the chemical side of the effects of 
lack of oxygen (of which we have mentioned only a few), 
we have very few biological observations on the same sub- 
ject. Even careful search of the literature discloses little 
more than the fact that all animal life-phenomena cease 
sooner or later in the absence of oxygen, that in higher 
animals the phenomena of dyspnoea precede death, and that, 
as Kihne showed’ the protoplasm becomes vacuolated and 
opaque and disintegrates. The observations made upon 
mountain disease may also be mentioned under this head- 
ing. It did not seem possible to me that these facts ex- 
hausted all the biological effects of lack of oxygen. The 
fundamental importance of oxygen for all life-phenomena 
rendered it probable, @ priori, that an accurate investigation 
would yield a series of qualitative and quantitative changes 
in life-phenomena. Such an investigation is, of course, 
1 Physiologische Chemie, Vol. I, p. 126. 
2 Zeitschrift fiir physiologische Chemie, Vol. XIX. 
3 Untersuchungen tlber das Protoplasma, 1864, 
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