Full resolution (JPEG) - On this page / på denna sida - XVI. Respiration and Oxidation - II. The Exchange of Gas between the Blood, on the one hand, and Pulmonary Air and the Tissues, on the other
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
METHODS FOR DETERMINING RESPIRATORY EXCHANGE. £69
Regnault and Reiset’s Method. According to this method the animal
•or person experimented upon is allowed to respire in an inclosed Bpace. The
carbon dioxide is removed from the air, as it forms, by Strong caustic alkali, from
which the quantity may be determined, while the oxygen is replaced continually
in exactly measured quantities. This method, which also makes possible a direct
determination of the oxygen used as well as the carbon dioxide produced, has
since been modified by other investigators, such as Pfluger and his pupils, Seegen
and Nkwak, and Hoppe-Seyler, Rosenthal and Oppenheimer and especially
by Atwater and Benedict. 1
Pettenkofer’s Method. According to this method the individual to be
experimented upon breathes in a room through which a current of atmospheric
air is passed. The quantity of air passed through is carefully measured. As it
is impossible to analyze all the air made to pass through the chamber, a small
fraction of this air is diverted into a branch line during the entire experiment,
carefully measured, and the quantity of carbon dioxide and water determined.
From the composition of this air the quantity of water and carbon dioxide con-
tained in the large quantity of air made to pass through the chamber can be
calculated. The consumption of oxygen cannot be directly determined in this
method, but may be calculated indirectly by difference, which is a defect in this
method. The large respiration apparatus of Sonden and Tigerstedt as well
as of Atwater and Rosa 2
are based upon this principle.
Speck’s Method. 3
For briefer experiments on man Speck used the follow-
ing: He breathes through a mouthpiece with two valves, closing the nose with a
clamp, into two spirometer-receivers, where the gas-volume can be read off very
accurately. The air from one of the spirometers is inhaled through one valve
and the expired air passes through the other into the other spirometer. By means
of a rubber tube connected with the expiration-tube an accurately measured part
of the expired air may be passed into an absorption-tube and analyzed.
Zuntz and Geppert’s Method.* This method, which has been improved by
Zuntz and his pupils from time to time, consists in the following: The individual
being experimented upon inspires pure atmospheric air through a very wide feed-
pipe leading from the open air, the inspired and the expired air being separated by
two valves (human subjects breathe with closed nose by means of a soft-rubber
mouthpiece, animals through an air-tight tracheal canula). The volume of the
expired air is measured by a gas-meter and an aliquot part of this air collected and
the quantity of carbon dioxide and oxygen determined. As the composition of
the atmospheric air can be considered as constant within a certain limit, the
production of carbon dioxide as well as the consumption of oxygen may be readily
calculated (see the works of Zuntz and his pupils).
Hanriot and Richet’s Method 6
is characterized by its "simplicity. These
investigators allow the total air to pass through three gasometers, one after the
other. The first measures the inspired air, whose composition is known. The
second gasometer measures the expired air, and the third the quantity of the
x
See Zuntz in Hermann’s Handbuch, 4, Thl. 2, and Hoppe-Seyler, Zeitschr. f.
physiol. Chem., 19; Rosenthal, Arch. f. (Anat. u.) Physiol., 1902; Zuntz and Oppen-
heimer, Arch.’ f. (Anat. u.) Physiol., 1905, and Bioch. Zeitschr., 14; Atwater and
Benedict, Bull. Dept. of Agriculture, Washington, 69, 109, and 136. See also Krogh,
Wien. Sitz. Ber., 115, III., and Skand. Arch. f. Physiol., 18.
2
Pettenkofer’s method; see Zuntz, 1. c; Sond6n and Tigerstedt, Skand. Arch,
f. Physiol., 6; Atwater and Rosa, Bull, of Dept. of Agriculture, 63. Washington.
1
Speck, Physiologie des menschlichen Atmens. Leipzig, 1892.
4
Pfluger’s Arch., 42. See also Magnus-Levy in Pfluger’s Arch., 55, 10, in which
the work of Zuntz and his pupils is cited.
5
Compt. Rend., 104.
<< prev. page << föreg. sida << >> nästa sida >> next page >>
