The Study of Human Implements 183 
whether the advent of metal at first added any new invention to 
man’s implements though it greatly increased their efficiency (the 
fish-hook may perhaps have been an exception). On the other hand 
there was a great efflorescence of elaboration in the form of orna¬ 
mentation. It is indeed quite late on in the period of metal that 
there appeared implements such as the scissors and its allies which 
metal alone made possible. 
Parallel evolution and reversion have their examples in human 
implements as in biology. The hand-dagger of iron of the middle 
ages was essentially a reversion in metal to. the hand-axe of the 
Palaeolithic period, and amongst the examples of incompletely 
perforated Neolithic axe-heads are specimens in which a central plug 
demonstrates the use of a type of boring implements which would 
appear to have lapsed but has reappeared in the “self-centering” bit 
of the present-day carpenter. 
Turning to modern times we find that several of the types 
represented in the Stone age have become phyla, embracing a vast 
variety of forms exhibiting every degree of specialisation and 
complexity. We can see in the stone saw the origin of the band saw, 
circular saw, fret saw, rip saw, etc., and in the hand-axe the fore¬ 
runner of the battle-axe, the hatchet, the adze, the hoe, etc. 
Consideration of the more complex types of implements em¬ 
phasises the fact that each new advance is in the nature of an 
increase in complexity and by a process of survival of the fittest this 
is followed by a period of simplification. Here too we see the analogy 
with biological phenomena as also in the origin of new types from 
the more generalised rather than the highly specialised examples. 
When we attempt to classify human implements into species, 
genera, families, cohorts, phyla, etc., we are presented with much the 
same difficulties as in the animate kingdoms, despite the advantages 
'which a knowledge of their chronological sequence confers. 
How, for example, would one classify the “safety razor”? Is it a 
derivative of the ordinary razor and therefore to be placed in the 
same class as the knife and the sword or is it a lineal descendant of 
the plane and therefore of the hide-scraper of Palaeolithic Man? 
Or again, is the cooper’s drawknife a derivative of the spokeshave 
which it morphologically resembles or is it a descendant of the 
hatchet to which it is perhaps more closely akin in function? 
What may be regarded as degenerate types which differ in func¬ 
tion whilst retaining morphological simplicity are well exemplified 
by the fish knife, the pallet knife, the butter knife, and many others. 
