The Study of Human Implements 181 
If on the other hand we consider the heavy hand axe of the Chellaean 
period, coarsely flaked on both faces, and compare it with the 
“heron” type with its tapering point and more or less triangular 
section we realise as we pass to the Moustierian epoch that this type, 
though so little different from the normal one, was in reality the 
evolutionary starting-point of the pick-axe and the hand-drill, the 
origin that is of entirely new classes of implements. 
A consideration of such examples helps one to realise that the 
differences in structure which serve to distinguish species of Chlamy- 
domonas or Bacteria are necessarily small as compared with those 
separating Capsella heteris from Cap sella simplex or Silene nutans 
from Silene duhia ; yet such small differences in a relatively un¬ 
differentiated group, which has not lost its plasticity by division of 
labour, may be the inception of fundamental evolutionary changes. 
The value of the character, whether in the organism or organ, must be 
considered relative to the complexity or simplicity of its organisation. 
When we pass from the Chellaean to the Acheulaean period the 
diminishing size of the flaking involving a higher grade of technique 
seems a relatively small development, but this increased dexterity 
made possible the thinner implements of the Moustierian period, with 
one plane face, which resulted in the marked development of the 
hafted axe in the split haft. It is in this period too that we find the 
flint drill and pick well developed whilst the finer flaking has also 
made possible the flint knife. 
Here again the distinction between the newly made knife of 
primitive man and the one which he had notched with constant 
use appears a comparatively slight one until we realise that the 
latter was the initiation of an evolutionary series beginning with 
the flint saw, and leading on to an entirely new phylum of man’s 
tools, including a variety of implements of abrasion from the cross-cut 
of the lumberman to the file of the locksmith. So too in the rude 
scraper of Palaeolithic Man there is little to indicate its manifold 
derivatives, from the barrasquit d’Espourga, used to shave off the 
bark in the Landes, or the spokeshave of the wheelwright, to the 
fillisters and moulding planes of the cabinet-maker. 
In the Neolithic period with its enormous advance in technique 
we find many of the dormant potentialities of the earlier types 
realised. The knives, picks, and saws had reached a high stage of 
development whilst the perfection of the boring implements is shown 
in the perforated stone axe-heads and the eyelet-holes of their bone 
needles. The hand-axe of earlier periods had already in the Palaeo- 
