Information Technology Reference
In-Depth Information
A generation before Boscovich, Newton, having determined "the motions of the
planets, the comets, the Moon and the sea", was unfortunately unable to determine the
remaining structure of the world from the same propositions because, as Newton said:
"I suspect that they may all depend upon certain forces by which the particles of the
bodies, by some causes hitherto unknown, are either mutually impelled towards one
another, and cohere in regular figures, or are repelled and recede from one another. These
forces being unknown, philosophers have hitherto attempted the search of Nature in vain;
but I hope the principles laid down will afford some light either to this or some truer
method of philosophy".
(Preface to the Principia).
But neither Newton nor Boscovich had the present-day experimental access to the
atomic and molecular level necessary for the understanding of chemistry and biochemistry.
Boscovich was just one in the long tradition of atomism, which had started with
Leucippus and Democritos, and which was promoted by Lucretius in his Latin poem, "On
the Nature of the Universe" which sought to explain everything in terms of atoms
6
.
Lucretius specifically claimed that mind and spirit are both also made of atoms. Atomism
has long been a difficulty for the Vatican, most recently in connection with allergy to gluten
and its implications for the doctrine of transubstantiation, but Lucretius' programme is
steadily becoming reality.
Atoms became visible after the proof of their arrangement in crystals of sodium
chloride by Lawrence Bragg and William Bragg, following the discovery of X-ray
diffraction in 1912 by Laue, Friedrich and Knipping. Explaining everything in terms of
atoms then became a major feature of modern science, especially of molecular biology
7
.
2. Towards a theoretical biology
In the 1920s and 1930s around the laboratory of F. Gowland Hopkins ("the father of
biochemistry") in Cambridge, there flourished the Club for Theoretical Biology, which was
a most important source of ideas about molecular biology. The key idea was that the three-
dimensional structure of molecules determined their behaviour. The group included Joseph
Needham, Conrad Waddington, Desmond Bernal, Lancelot Whyte
8
, and others. They
aimed to make biology a real science like physics, where there were interactions to and fro
between theory and experiment, and to understand the origin and processes of life. They
also had radical political ideas. Theoretical biology was a new concept. Darwin had
formulated the principles of evolution by natural selection, but now there was a prospect of
elucidating the mechanisms of heredity, which appeared to operate at the atomic level.
Needham made a proposal (1935) for an Institute of Physico-chemical Morphology
(to the Rockefeller Foundation, through Warren Weaver) but this was not funded, although
Weaver and Astbury (independently) had coined the expession 'Molecular biology'.
Needham as an embryologist had to ask how shape and the unfolding of shape in the
embryo following a programme, was determined by the hereditary material.
Already at that time (1931) Bernal
9
had recognised that in order to be replicated, the
hereditary material, then thought to be protein, had to be a linear structure. It was not
demonstrated until 1944 that genes were nucleic acids and not protein (although associated
with protein)
10
. In 1934 Bernal showed that if a crystal of pepsin were kept in its mother
liquor, the diffraction pattern had information out to inter-atomic dimensions, that is, a
protein molecule has every atom in its proper place. This was an epoch-making discovery.
The concept of a mystical protoplasm thus collapsed. Proteins had a structure which could
be investigated by physical methods, chiefly X-ray crystal structure analysis. Bernal and
Astbury agreed to divide the new world between themselves, Bernal taking the globular
