290 Proceedings of Poyal Society of Edinburgh. [sess. 
anhydride is absorbed by potash, the oxygen by pyrogallic acid, 
whilst the amount of nitrogen is represented by what remains. 
(a) Blood of Sepia officinalis. 
100 volumes of the blood of the cuttle-fish contained the follow- 
ing volumes of the three gases — the volumes being reduced to 0° C. 
and 760 mm. : — 
I. 
II. 
III. 
IV. 
Y. 
YI. 
Oxygen, 
13-26 
12-91 
13-14 
14-62 
14-21 
14*34 
Carbonic anhydride, 
30-12 
31-21 
32-10 
30-14 
29-12 
29-89 
Nitrogen, 
1-60 
2-00 
1-51 
1-41 
1-73 
1-23 
The nitrogen is simply dissolved in the blood, but the oxygen 
and carbonic anhydride are partly dissolved, and partly in a state 
of loose chemical combination with certain constituents of the blood. 
The oxygen with the haemocyanin ; and possibly the greater part 
of the carbonic anhydride is united to certain salts contained in the 
blood. 
( b ) Blood of Cancer pagurus. 
The blood was obtained from very large individuals, by opening 
the carapace and passing the capillary point of the canula directly 
into the heart. 
100 volumes of the blood yielded the following volumes of 
oxygen, carbonic anhydride, and nitrogen, after being reduced to 
0° C. and 760 mm. : — 
I. 
II. 
III. 
IY. 
Oxygen, ...... 
14-79 
14-88 
14-96 
14-85 
Carbonic anhydride, 
28-62 
27-21 
27-14 
28-39 
Nitrogen, 
1-01 
1-20 
1-22 
1-30 
