CONNECTION BETWEEN BLOOD AND ITS GASES. 7 7 1 
Setschenow l calculated that serum held in simple solution 99 per 
cent, of the amount of carbon dioxide which distilled water would 
absorb under similar conditions, and that one-tenth of the total carbon 
dioxide in the scrum of dog's blood was in simple solution. The result 
of further experiments made by Zuhtz 2 upon these points is shown in 
the table on p. 770. 
In the next place, it is necessary to consider the amount of carbon 
dioxide in loose and firm chemical combination with substances in the 
corpuscles, plasma and serum. Most of the gas is contained in the 
plasma or serum, for these fluids contain a larger quantity of carbon 
dioxide than that which can be obtained from an equal volume of blood. 
The greater quantity of the gas is in a state of loose chemical combination 
in the serum, for much of it can be extracted by the action of the 
vacuum of a 1 »lood-pump ; the remainder, however, is in firm chemical 
combination, and is only set free in the pump by the addition of an 
acid. In this respect a marked contrast is observed between blood and 
serum, for all the carl ton dioxide can be extracted from the former by 
the action of the vacuum alone, the haemoglobin of the red corpuscles 
playing, apparently, the part of an acid. 3 
The following table shows the amount of carbon dioxide in loose and 
firm chemical combination in serum : — 
Carbon Dioxide in Serum. 
(Volumes percent.) 
Carbon* Dioxide in 
Blood. 
(Volumes per cent.) 
Observer. 
Extracted by 
Vacuum. 
In Firm Com- 
bination. 
Total in Com- 
bination. 
13-4 
21-1 
44-6 
35-2 
19-9 
22-0 
22-5 
26-9 
31-3 
21-9 
4-9 
9-3 
6-9 
12-4 
13-5 
17-0 
44-7 
43-0 
49-5 
44-5 
26-8 
34-4 
36-0 
43-9 
34-5 
35-0 
Schceffer. 4 
Pfliiger. 3 
Zuntz. 6 
9; 
The differences in these results are due, as Zuntz " has pointed out, 
to the powerful action of Pfliiger's pump, and to the concentration of the 
serum during its exposure to the vacuum. The carbonates of the serum give 
off their gas more readily when the solution is concentrated ; this complication 
1 Loc. cit., Centralbl. f. d. vied. Wisscnsch., Berlin, 1877, No. 35. 
- Hermann's "Handtmch," Bd. iv. Th. 2. S. 68. 
3 Setschenow, Sitzungsb. d. k. Akcul. d. Wissensch., Wien, 1859, . Bd. xxxvi. S. 293 ; 
Pfliiger, "Ueber die Kohlensaure des Brutes," Bonn, 1864, S. 5 ; Zuntz, Centralbl. f. d. 
vied. Wissensch., Berlin, 1867. S. ~.<'i~ . 
4 Sitzungsb. d. 1: Akad. d. Wis*ensch. Math.-naturw. CI., Wien, 1860, Bd. xli. S. 616. 
5 "Ueber die Kohlensaure des Blutes," Bonn, 1864, S. 11. 
ti Centralbl. f. d. mat. Wissensch., Berlin, 1867, S. 529; Hermann's "Handbuch," 
Bd. iv. Th. 2, S. 45. 
7 Loc. cit. 
