The evolution of living organisms / by Edwin S. Goodrich.

  • Edwin Stephen Goodrich
Date:
[1912]
Catalogue details

Licence: Public Domain Mark

Credit: The evolution of living organisms / by Edwin S. Goodrich. Source: Wellcome Collection.

    14/118 (page 10)
    good in living things as they do in inorganic nature. All the matter which enters an organism as food and oxygen eventually leaves it as waste product, except in so far as it is retained for purposes of growth. Similarly all the energy brought in is balanced by work done and heat given off. Neither new matter nor new energy are pro¬ duced, although both are undergoing unceasing change. This is the metabolic process in terms of physics and chemistry; it is quite characteristic of living things. There is no life without metabolism, and no meta¬ bolism without life. In the living engine not only is the food consumed, but the machinery itself is involved in the process of change, so that the food material brought in does not for the most part merely pass through as fuel; it serves to build up that complex living substance, or machinery, which is perpetually breaking down again into non-living matter. Chemical instability, a tendency to unite with other sub¬ stances, or to break up into simpler groups, is manifested by these highly complex protein molecules. There is thus a double process continually going on in metabol¬ ism. A building up or synthesis of substances to form higher and higher compounds in the making of which energy is absorbed—this is the anabolic process ; and a corresponding breaking down of these highest compounds into simpler ones, and eventually into waste products, during which energy is freed—called the katabolic pro¬ cess. In living substance there are, then, two series of compounds : one leading up to the highest complexity, and the other leading down to waste products, from which energy is no longer drawn. This mixture of a double stream of substances undergoing these physico-chemical changes is the living matter itself, the very physical basis of life, knovrn as protoplasm. In physical structure protoplasm is a viscid or semi¬ liquid colourless substance; seen under the highest powers of the microscope it appears to be composed of the minutest globules of a more liquid substance enclosed in a meshwork of denser fluid. Chemically it is composed of a variety of anabolic and katabolic proteins, asso-