193 
ri h 1914. Nuphar root. Intercellular air.. . 11,2 °/o 0 2 . 
— Cocoon air. 8,6 °/o O,. 
Diff. + 2,6 °/o 0 2 . 
9 /7 — Intercellular air. 2,6 °/o 0 o . 
— Cocoon air. 1,0 °/o 0 9 . 
Diff. + 1,6 °/o 0 2 . 
/ 
2 h — Typha root. Intercellular air. 7,4 °/o 0 o . 
— Cocoon air. 2,4 °/o 0 2 . 
Diff + 5,5 °/o 0 2 . 
11 1 9 1913 Intercellular air. 13,1 °/o 0 2 . 
— Cocoon air. 10,2 °/o 0 2 . 
Diff + 2,9 °/o 0 2 . 
As the main result of these analyses we must lay stress upon 
the faet that the oxygen percentage always is lower in the cocoon 
than in the intercellular spaces with which it communicates; 
oxygen will therefore diffuse from the intercellular spaces into the 
cocoon, but we cannot yet decide whether this is the only way in 
which the air in the cocoon can be renewed; the oxygen in the 
water might be of some importance too 1 ). 
The following experiment shows that the oxygen in the water 
is without influence upon the renewal of the air in the cocoon. 
An uncompleted cocoon — that is a cocoon in which the 
hole through the wall still not is gnawed — was for 3 hours 
enclosed in water saturated with atraospheric air; after that the 
composition Of the air was determined, and the result was that the 
air only contained a trace of oxygen 2 ). 
9 Babak writes (in Wintersteins Handbuch I 2 , p. 471): “Allerdings kann 
der Luftinhalt (in the cocoon) auch durch Diffusion aus dem Wasser 
sauerstofhaltig bleiben”. 
2 ) According to the analysis the 0 2 percentage .was 0,07 °/o but this is 
within the limit of errors; moreover we must remember that on 
account of the diffusion the 0 2 percentage under such conditions 
must be found a little higher than it really is. 
Vidensk. Meddel, fra Dansk naturh. Foren. Bd. 66. 13 
