128 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
deep-sea waters the volumes of oxygen were, in general, less than those calculated 
from the nitrogen-volumes on the hypothesis of surface absorption of air at the 
temperature corresponding to the nitrogen found. In waters from great depths the 
actual volume of oxygen was often very small.” “It is worth noting, however, that 
very small quantities of oxygen present themselves occasionally at moderate depths.” 
Two examples are here given: 
Cubic centime- 
ters per liter. 
0 2 calcu- 
lated. 
Depth 
(fat.h- 
Per cent 
of 0 2 in 
dissolved 
gas. 
n 2 . 
0 2 . 
oms). 
15. 08 
0.6 
8.21 
2,875 
4.33 
13.74 
1.65 
7.15 
300 
10. 72 
The Challenger expedition did not find any deep-sea waters that were entirely 
free from absorbed oxygen. In the surface-waters the amount of oxygen absorbed 
from air at a given temperature is the product of its coefficient of absorption into its 
partial pressure in the undissolved residue. Hence, in surface water, at given tem- 
perature and 760 mm. pressure, there would be the following result: 
Tempera- 
ture C. 
Dissolved N 2 and 0 2 in 
c. c. 
Per cent of 
0 2 in 
dissolved 
gas. 
N 2 . 
0 2 . 
0° 
15.60 
8. 18 
34.40 
35° 
8.36 
4. 17 
33. 31 
In the first table we find the per cent of oxygen in the dissolved gases to be 4.33 
per cent and 10.72 per cent respectively, which, compared with the 0 2 per cent in 
surface waters in the second table, shows an enormous deficit. As to the free C0 3 in 
the sea, I quote again from the Challenger report: “From all the evidence afforded 
by the Challenger research we see that free carbonic acid in sea waters is the excep- 
tion.” It would thus seem that there is every condition offered for the elimination 
of CO., from living organism, as by the gills of fishes, and the immediate absorption 
of this waste product by the surrounding water. It is at least a strange coincidence 
that with the gradual diminution of oxygen in the water, according to the depth, we 
find an increase in percentage of oxygen contained in the bladder. Biot cites Trygla 
lyra from 500 fathoms containing 87 percent oxygen; Sparus argenteus from 65 
fathoms contained 50 per cent oxygen; Spar us dentex from 20 fathoms contained 40 
per cent oxygen. My own observations on Lopholatilus taken from 55 fathoms 
showed 66.5 per cent oxygen, and from 70 fathoms showed 69 per cent of oxygen. 
May not this process be one directly to supply the animal with more oxygen under 
these conditions, where the oxygen dissolved in the water is so deficient? Such an 
explanation is tenable, inasmuch as Hiifner, Bohr, Moreau, and Haldane have shown 
by experiment that the gas is the result of an active secretion in which almost pure 
oxygen may be given to the bladder. 
It occurred to me, if this process existed for the purpose of supplying oxygen 
to the animal, that changes in the proportion of the constituent gases would be found 
when the animal was partially or completely asphyxiated, and that these changes 
