Full resolution (JPEG) - On this page / på denna sida - XVII. Metabolism - IV. The Dependence of Metabolism on other Conditions
<< 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.
930 METABOLISM.
like a cold-blooded animal, and the metabolism decreases parallel with
the body temperature. In normal animals, on the contrary, the body
temperature can be kept constant, on lowering the external temperature,
by an increased metabolism; but also in such animals because of a rise
in the external temperature a rise in the metabolism above a certain
limit can also take place.
A very interesting and important question is the action of high altitude
upon the oxidation processes, the economy of temperature, the protein
exchange and the general metabolism. The results of the laborious
and important investigations on this subject may, be found in the large
work of N. Zuntz, A. Loewy, F. Muller and W. Caspari.1
That the ingestion of food raises the metabolism has been known for
a rather long time, and this has been studied by Zuntz, v. Mering, Mag-
nus-Levy, Voit, Rubner, Johansson and collaborators, also by Heilner
and by Gigon.2
It follows from these investigations that this rise in
metabolism, which in man, on sufficient supply of food, amounts to a rise
of 10-15 per cent of the basal requirement and with abundant supply of
food may be still larger (35 per cent in the researches of Johansson,
Tigerstedt and collaborators), has a double cause, namely, partly a
digestion work (Zuntz) and partly a chemical decomposition (specific
dynamic action of Rubner) which takes place at the same time.
The sum of all the work which is necessary for the chemical trans-
formation of the foods, as well as for the mechanical division and trans-
portation of the food in the intestinal canal, is called the digestion work by
Zuntz. That such work exists has been shown by Zuntz and v. Mering
by comparative tests of the different action upon metabolism by
foods introduced per os and intravenously, and recently Cohnheim 3
has shown that in sham feeding an increased catabolism of non-
nitrogenous body constituents took place. The influence of digestion
work in Zuntz’s sense is especially apparent in herbivora, in which this
work, according to Zuntz and collaborators, may amount to the consump-
tion of more than 50 per cent of the total energy content of the raw
fodder.
1
Hohenklima und Bergwanderungen in ihrer Wirkung auf den Menschen, Berlin,
1906.
2
Zuntz and v. Mering, Pfluger’s Arch., 15; Zuntz, Naturw. Rundschau, 21 (1906),
with Hagemann, 1. c, with Magnus-Levy, Pfluger’s Arch., 49; Magnus-Levy, ibid.,
55, and v. Noorden’s Handbuch; Voit, Hermann’s Handbuch, 6; Rubner, Zietschr.
f. Biol., 19 and 21; and Arch. f. Hyg., 66; Johansson, Skand. Arch. f. Physiol., 21,
with Koraen, ibid., 13; Heilner, Zeitschr. f. Biol., 48 and 50; Gigon, Pfluger’s Arch.,
140.
’Arch. f. Hyg., 57.
<< prev. page << föreg. sida << >> nästa sida >> next page >>
