GASES OF THE BLOOD. 
759 
made when Ludwig and Setschenow, 1 Pfliiger 2 and Helmholtz, 3 constructed 
their mercurial gas-pumps, based upon the principle of the Torricellian vacuum. 
The mercurial gas-pump.- -Numerous forms 4 of this apparatus have been 
introduced, but here it is only necessary to mention Pfliiger's pump, the 
modification of this made by Gr6hant, s ami the simple apparatus devised by 
Leonard Hill. The principle of the first is shown in the diagram on p. 758. 
Further details upon the construction and working of these pumps will 
be found in text-hooks of physiological chemistry. 6 
In Leonard Hill's 7 gas-pump, the chief advantages are simplicity, cheap- 
ness, and rapidity of art inn; 
the working errors are under 
1 per cent., and only small 
quantities of blood are required. 
The construction of the pump 
is shown in Fig. 70, and 
the successive manipulations 
are as follows : — "A, blood- 
receiver (F) is affixed to the 
end of the tube E, and the 
receiver is elevated into the 
position indicated by the dotted 
outline. The reservoir (B) is 
then put in connection with 
the tube (E) by means of the 
three-way tap (D), the reservoir 
(A) is raised above the pump, 
and the whole system is filled 
with mercury to the top of the 
blood-receiver (F). The screw- 
clip on the rubber tube at the 
upper end of F is then closed, 
and the reservoir (A) lowered 
until the blood-receiver is ex- 
hausted, except for 2 or 3 c.c. 
of mercury, which is purposely 
left within. The screw-clip on 
the lower end of F is next closed, 
and the blood-receiver now 
clipped at either end, exhausted, 
detached from tube E, and 
weighed. A sample of blood is 
then collected. The arterial or 
venous cannula is filled with 
blood, and immediately afterwards pushed into the rubber tube at the 
1 Sitzungsb. d. k. Akad. d. Wissensch. Math-phys. CI., Wien, 1859, P>d. xxxvi. S. 293. 
2 " Untersucli. a. d. Bonner physiol. Lab.," 1865, S. 188; Ccntralbl. f. d. med. 
Wissensch., Berlin, 1866, S. 305 ; Arch. f. d. gcs. Physiol., Bonn, 1S68, Bd. i. S. 61, 
3 See Zuntz, Hermann's "Haudbueh," Bd. iv. Th. 2, S. 27. 
4 \ Schmidt Ber. d. k. sacks. Gesellsch. d. Wissensch. Math-phys. CI., Leipzig, 186/, 
Bd xix S 33 ; Hoppe-Seyler, "Physiol. Chem.," Berlin, 1879, Bd. iii. S. 491 ; Nawrocki, 
Stud d. physiol. Inst. zuBreslau, Leipzig, Bd. ii. S. 144; Bnsch, Arch. f. d. ges. Physiol., 
Bonn, 1869, Bd. ii. S. 445 ; Kossel and Raps, Arch./. Physiol., Leipzig, 1893, S. 198. 
5 Paul Bert, " Lecons sur la physiol. conip. de la respiration," Paris, 1870, p. 102; 
"Lapression barom^trique, " Paris, 1878, p. 615. 
6 Halliburton, "Text-Book of Chemical Physiology and Pathology, London, 1891, p. 
30; Hempel, " Gasanalytische Methoden;" Gamgee, "Physiological Chemistry of the 
Animal Body," vol. i. pp. 200-206. 
7 Journ. Physiol, Cambridge and Loudon, 1894-5, vol. xvn. p. -j.j3 
ibid., 1895, vol. xviii. p. 218. 
Fig. 70. — Leonard Hill's Gas-Pump. 
Hill and Xabarro, 
