12
MARCEL FLORKIN AND HOWARD S. MASON
step in comparative biochemistry—"they can be detected everywhere
in the organized world, so that we can regard them as constant, concomitant phenomena of life." Enzymes were found in bacteria, in yeasts,
molds, in the sap and organs of higher plants, in insects and lower
animals, in fishes, amphibia, and mammals. And, more important, "of all
the multitudinous chemical processes in the living cell on which life
depends, there is scarcely one which is not due to enzyme catalysis;
there can be no life without enzymes" (6). This is a comparative
generalization of transcendant importance because it describes one of
the central unities of life. Such a generalization cannot be absolute because only a small proportion of the approximately two million living
species has been investigated from this point of view, but it is obvious
that, if plentiful examples can be drawn from every level of the phylogenetic scale and if no exceptions can be discovered, the probability
that it is true for life in general is very high. This is also true of other
comparative generalizations. On the other hand, the extent of biochemical diversity, which is very interesting in its own right, can only
be determined by study of all living organisms. Nevertheless, there may
be principles which govern its kinds and extent; these principles may
well be discovered before the whole range of living species has been
investigated.
Another major biochemical unity which became apparent in the
nineteenth century concerned the biological conservation of energy. The
principle of energy conservation, the first law of thermodynamics, had
been developed by the work of Benjamin Thompson, J. R. Mayer, and
von Helmholtz (1847), who extended the idea to biology. Evidence
that the principle was applicable to living organisms was subsequently
obtained by Rubner (1885), and Atwater and Bryant (1899), and
provided experimental basis for the belief that the same laws which
describe the transformations of energy in inanimate matter also describe
them in living organisms.
Thus, the evolution of nineteenth century organic and physical
chemistry provided the groundwork for major generalizations about
biochemical unity. During the same period, some interest in the comparative aspects of biochemistry as such was also manifest, not only
with respect to the structural composition, distribution and metabolism
of the chemical components of living organisms, but also in regard to
the relationship of these characteristics to the physiological, genetic,
evolutionary, and ecological properties of life. In 1886, Krukenberg
devoted attention to comparative biochemistry in his "Vergleichendphysiologische Vorträge," and Griffiths, in 1892, wrote a whole volume
on the subject, entitled "Physiology of Invertebrata." This, unfortunately,
MARCEL FLORKIN AND HOWARD S. MASON
step in comparative biochemistry—"they can be detected everywhere
in the organized world, so that we can regard them as constant, concomitant phenomena of life." Enzymes were found in bacteria, in yeasts,
molds, in the sap and organs of higher plants, in insects and lower
animals, in fishes, amphibia, and mammals. And, more important, "of all
the multitudinous chemical processes in the living cell on which life
depends, there is scarcely one which is not due to enzyme catalysis;
there can be no life without enzymes" (6). This is a comparative
generalization of transcendant importance because it describes one of
the central unities of life. Such a generalization cannot be absolute because only a small proportion of the approximately two million living
species has been investigated from this point of view, but it is obvious
that, if plentiful examples can be drawn from every level of the phylogenetic scale and if no exceptions can be discovered, the probability
that it is true for life in general is very high. This is also true of other
comparative generalizations. On the other hand, the extent of biochemical diversity, which is very interesting in its own right, can only
be determined by study of all living organisms. Nevertheless, there may
be principles which govern its kinds and extent; these principles may
well be discovered before the whole range of living species has been
investigated.
Another major biochemical unity which became apparent in the
nineteenth century concerned the biological conservation of energy. The
principle of energy conservation, the first law of thermodynamics, had
been developed by the work of Benjamin Thompson, J. R. Mayer, and
von Helmholtz (1847), who extended the idea to biology. Evidence
that the principle was applicable to living organisms was subsequently
obtained by Rubner (1885), and Atwater and Bryant (1899), and
provided experimental basis for the belief that the same laws which
describe the transformations of energy in inanimate matter also describe
them in living organisms.
Thus, the evolution of nineteenth century organic and physical
chemistry provided the groundwork for major generalizations about
biochemical unity. During the same period, some interest in the comparative aspects of biochemistry as such was also manifest, not only
with respect to the structural composition, distribution and metabolism
of the chemical components of living organisms, but also in regard to
the relationship of these characteristics to the physiological, genetic,
evolutionary, and ecological properties of life. In 1886, Krukenberg
devoted attention to comparative biochemistry in his "Vergleichendphysiologische Vorträge," and Griffiths, in 1892, wrote a whole volume
on the subject, entitled "Physiology of Invertebrata." This, unfortunately,