190 
13 /n 1914. Air from a Nuphar root. 2,4 °/o 0 2 . 
22 /l2 - “ - - - - . 
26 /i — Air from a Nuphar rhizoma. 
ii 
Air from a Typha root 
14 /7 1914. Air from the rhizoma of Potamogeton 
natans. 
13 /t — Ranunculus lingva, root. 
2,4 
°/o 
0 2 . 
1,9 
°/o 
o 2 . 
0,4 
°/o 
0 2 . 
13,2 
°/o 
o 2 . 
9,3 
°/o 
o 2 . 
6,6 
°/o 
0 2 . 
3,0 
°/o 
0 ,. 
on 
s— 
12 . 
1,2 
°/o 
0 2 . 
4,5 
°/o 
0 2 . 
9,4 
°/o 
0 2 . 
4,9 
°/o 
0 2 . 
The results of these analyses are that the composition of the 
air in the intercellular spaces of different aquatic plants is very 
variable. The oxygen percentage is low, rarely higher than 10 °/o 
and can, especially during winter, sink to about 1 — 2 °/o and 
even still less. 
The intercellular air is in other words far from being an 
“oxygen-rich gasmixture”, this expression, most favoured by the 
former Authors when referring to the air which the larva should 
inspire from the intercellular spaces, is consequently a little 
unfortunately chosen. 
The faet that the oxygen percentage in the air from the 
above mentioned roots and rhizomes is low can of course not have 
any influence on the main question regarding the respiration of 
the larvae: moreover we have learned that the animal cannot 
/ 
breath the oxygen dissolved in the water; — the animal must 
therefore use the oxygen contained in the intercellular spaces of the 
roots and rhizomes of aquatic plants. 
The only way in which this can take place seems to be by 
active inspiration through the canals in the hooks. 
