a disordered working of the great bowel. Why this
part of our bodily machinery should fail us under modern conditions of
diet becomes quite apparent when we survey the history of man's distant
past. For the anthropologist there are only two well-marked phases in
human history. The first phase is that of Natural subsistence--an
infinitely long and monotonous chapter, stretching over a million of
years or more. The second is the phase of Artificial subsistence--a
short chapter covering a period of 10,000 or 12,000 years at the utmost,
but a period crowded with events which have a critical bearing on our
present and future welfare. In the first or long phase mankind was
broken into small and scattered groups which gained as best they could a
sparse, uncertain, and coarse sustenance from the natural produce of
shore and stream, moorland and woodland. In the second or short phase
man conquered nature; by means of cultivation and domestication he
forced from the soil a sure and abundant supply of food, thus rendering
possible the existence of our modern massed populations. Now the
machinery of man's body and the instinctive outfit of his brain, which
had been evolved to answer to the conditions of life presented by the
first long phase of his history, were also those which had to serve him
when he entered the new conditions of the short or modern phase. We need
not be surprised to find, then, that part of his ancient outfit is ill
adapted to modern conditions of life. Man's great bowel, including the
caecum, appendix, and colon, which answered his needs well when his
dietary was coarse and uncooked, is ill contrived to deal with foods
which are artificially prepared and highly concentrated. A school, which
was headed by the late Professor Metchnikoff, even goes so far as to
maintain that man would be improved by the complete removal of his great
bowel--a doctrine with which I totally disagree. We are all alive to the
fact that there is a lack of harmony between the ancient machinery of
our bodies and the modern conditions under which we live, but we are
only now awakening to the fact that what is true of our bodies is also
true of our minds. In that immense first phase of our history an
elaborate mental machinery had been evolved for binding small groups of
mankind into social units. This subconscious or instinctive mental
outfit, we shall see, is part of the machinery which Nature has employed
in the evolution of races of man