A text-book of physiological chemistry / Olof Hammarsten ; authorized translation from the author's enlarged and revised 4th German edition by John A. Mandel.

  • Olof Hammarsten
Date:
1900
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Licence: In copyright

Credit: A text-book of physiological chemistry / Olof Hammarsten ; authorized translation from the author's enlarged and revised 4th German edition by John A. Mandel. Source: Wellcome Collection.

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    products exactly the above-mentioned chief components of the nutrition of })lants, namely, carbon dioxide, water, and ammonia derivatives, which are rich in oxygen and have little energy. '^I'he chemical tension, which is partly combined with the free oxygen and partly stored up in the above- mentioned more complex chemical compounds, is transformed into living force, heat, and mechanical work. While in the jdant reduction processes and svntheses, which are active in the conversion of living force into potential energy or chemical tension, are the prevailing forces, we find in the animal body the reverse of this, namely, cleavage and oxidation processes, which convert chemical tension into living force {viH viva). This difference between animals and plants must not be overrated, nor must we consider that there exists a sharp boundary-line between the two. This is not the case. There are not only lower plants, free from chloro- phyll, which in regard to chemical processes represent intermediate steps between higher plants and animals, but the difference existing between the higher plants and animals is more of a quantitative than a qualitative kind. Plants require oxygen as peremptorily as do animals. Like the animal, the plant als6, in the dark and by means of those parts which are free from chlorophyll, takes uj) oxygen and eliminates carbon dioxide, while in the light the oxidation processes going on in the green parts are overshadowed or hidden beneath the more intense reduction processes. Like the animal the fermentive fungi transform chemical tension into living energy and heat; and even in a few of the higher plants—as the aroidem when bearing fruit—a considerable development of heat has been observed. The reverse is found in the animal organism, for, besides oxidation and splitting, reduc- tion processes and syntheses also take place. The contrast which seemingly exists between animals and plants consists merely in that in the animal organism the processes of oxidation and splitting are prevalent, while in the plant those of reduction and synthesis have thus far been observed. Wohler’ in 1824 furnished the first example of synthetical PROCESSES within the animal organism. He showed that when benzoic acid is introduced into the stomach it reappears as hippuric acid in the urine, after it combines with glycocoll (amido-acetic acid). Since the discovery of this synthesis, which may be expressed by the following equation, C,H,.C001I + NH,.Cir,.C001I = TsHl(C.H,.C()).CH,.COOH + Benzoic acid Glycocoll Hippuric acid and which is ordinarily considered as a type of an entire series of syntheses occurring in the body where water is eliminated, the number of known syntheses in the animal kingdom has increased considerably. Many of these syntheses have also been artificially produced outside of the organism, ‘ Berzelius, Lebrb. d. Cbemie, Ubersetzt vou Wbhler, Bd. 4. Dresden, 1831.
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