756 EVENING DISCOURSES. 
of the Pleistocene—a period we shall say of 400,000 years—is not more than 
sufficient. I am thus postulating in order to explain the differentiation and 
distribution of modern races, that mankind, at the beginning of the Pleistocene 
period, had reached a physical condition which has its best modern representa- 
tion in the aborigines of Australia. 
Is it not possible, however, that the evolution of man’s body may not be a 
story of slow, continuous, almost imperceptible change, but one of alternate 
spurt and quiescence? The human body is notoriously the subject of sport, of 
defects and malformations. Many of you will recall the book which Professor 
Bateson published eighteen years ago, entitled ‘ Material for the Study of Varia- 
tion.” The work contained many facts which seemed to indicate that the animal 
body was subject to violent structural changes, and that a new form of being 
might be produced almost at a bound. We often see men in whom there is an 
extra vertebra in the loins, an additional rib, or a supernumerary digit, but we 
now recognise that these marked structural changes are merely the extreme 
manifestations of a normal degree of variation of which every man’s body is 
the subject. The bodies of men and anthropoids are notoriously liable to ana- 
tonfical variation, and we are justified for that reason in regarding their bodies 
as particularly plastic material in the hands of evolution. When, however, we 
come to examine the anatomical differences which separate one race of men from 
another we see that racial characters comprise, not those marked variations which 
so frequently are seen by the students of human anatomy, but a multitude of 
yinor structural features such as might slowly accumulate in the course of the 
differentiation of one race from another. When one comes to realise the extremely 
complex structure and finely adjusted nature of the human brain, it becomes 
very apparent that any addition to the most essential structure of the human 
body must be the result of an extremely slow process of growth. Only one line 
of evidence shakes our belief in the slow rate of human evolution, and that is 
the study of certain diseases of growth to which man is liable. We have come to 
realise in recent years that we are, as regards face, figure, stature, and nature, 
largely what our internal glands and secretions have made us. Growth itself 
is definitely regulated by means of substances set free by certain glands of the 
body. We are absolutely certain that a marked disturbance of these glands will, 
in the course of a few years, definitely transfigure the individual to which they 
belong. Nature seems to have at her command a means for executing rapid 
advances, but when we survey what we know of man’s past history and mark the 
changes he is subject to in the present we see no sign of her having resorted to 
such a means. 
There is another route by which we may approach the problem of man’s 
antiquity. Man does not stand alone: he has distant and rather despised rela- 
tions—the great anthropoid apes. Although the structural hiatus between him 
and them is wide, yet when we compare the two types we see that there is a 
multitude of resemblances, so intimate and so peculiar that we cannot explain 
them except by supposing that man and the great anthropoids had a common 
ancestor at one stage of the earth’s history. The great anthropoids have also 
a distant and primitive living relative—the gibbon. The gibbon in turn, while 
foreshadowing in his body the structural peculiarities of his more august rela- 
tives, finds his cousins by descent in more lowly forms still—the monkeys of the 
Old World and the monkeys of the New. Of these two groups the monkeys of the 
New World are the nearest to the original stock which gave rise to the higher 
Primates. It was through such a lineage that man rose to reach his present 
estate. If, then, we are to ascertain the approximate date or, to putitin other 
words, the possible date at which man appeared, we must first search for the 
earliest traces of the basal form of the higher Primates which lead towards the 
human line. The earliest traces we have discovered as yet were described by 
Dr. Max Schlosser only two years ago. In the very oldest Oligocene formation 
of the Fayoum, Egypt, the teeth and jaws of three Primates were discovered. 
Two of these are allied to the South American apes, the other is a forerunner 
of the gibbons. These Fayoum fossils are of the highest importance to the solu- 
tion of our problem. Their discovery assures us that at such an early date in 
the evolution of mammals the South American apes and the pro-gibbons were 
already in existence. They are highly evolved forms and it is not unlikely that 
they appeared at a much earlier date. In European strata of the period following 
