OF INSECTS. 
191 
III. In the bivalve order of shell-fish, cockles, muscles, 
oysters, &c. what contrivance can be so simple or so clear, 
as the insertion at the back, of a tough, tendinous substance, 
that becomes at once the ligament which binds the two 
shells together, and the hinge upon which they open and 
shut. 
IV. The shell of a lobster’s tail, in its articulations and 
overlapping, represents the jointed part of a coat of mail; 
or rather, which I believe to be the truth, a coat of mail is 
an imitation of a lobster’s shell. The same end is to be 
answered by both; the same properties, therefore, are re¬ 
quired in both, namely, hardness and flexibility, a covering 
which may guard the part without obstructing its motion. 
For this double purpose, the art of man, expressly exercis¬ 
ed upon the subject, has not been able to devise anything 
better than what nature presents to his observation. Is not 
this, therefore, mechanism, which the mechanic, having a 
similar purpose in view, adopts? Is the structure of a coat 
of mail to be referred to art? Is the same structure of the 
lobster, conducing to the same use, to be referred to any¬ 
thing less than art? 
Some, who may acknowledge the imitation, and assent 
to the inference which we draw from it in the instance be¬ 
fore us, may be disposed, possibly, to ask, why such imita¬ 
tions are not more frequent than they are, if it be true, as 
we allege, that the same principle of intelligence, design, 
and mechanical contrivance, was exerted in the formation 
of natural bodies, as we employ in the making of the vari¬ 
ous instruments by which our purposes are served? The 
answers to this question are, first, that it seldom happens 
that precisely the same purpose, and no other, is pursued 
in any work which we compare, of nature and of art; sec¬ 
ondly, that it still more seldom happens, that we can imitate 
nature, if we would. Our materials and our workmanship 
are equally deficient. Springs and wires, and cork and 
leather, produce a poor substitute for an arm or a hand. In 
the example which we have selected, I mean a lobster’s 
shell compared with a coat of mail, these difficulties stand 
less in the way, than in almost any other that can be as¬ 
signed: and the consequence is, as we have seen, that art 
gladly borrows from nature her contrivance, and imitates 
it closely. 
But to return to insects. I think it is in this class of 
animals above all others, especially when we take in the 
