52 
OF MECHANICAL ARRANGEMENT 
sorting to appointment. Why, for instance, is the saliva, 
which is diffused over the seat of taste, insipid, whilst so 
many others of the secretions, the urine, the tears, and the 
sweat, are salt? W~hy does the gland within the ear sepa¬ 
rate a viscid substance, which defends that passage; the 
gland in the upper angle of the eye, a thin brine, which 
washes the ball? Why is the synovia of the joints mu¬ 
cilaginous; the bile bitter, stimulating, and soapy? Why 
does the juice which flows into the stomach, contain pow¬ 
ers, which make that organ the great laboratory, as it is by 
its situation the recipient, of the materials of future nutri¬ 
tion? These are all fair questions; and no answer can be 
given to them, but what calls in intelligence and intention. 
My object in the present chapter has been to teach three 
things: first, that it is a mistake to suppose that, in reason¬ 
ing from the appearances of nature, the imperfection of 
our knowledge proportionably affects the certainty of our 
conclusion; for in many cases it does not affect it at all: 
secondly, that the different parts of the animal frame may 
be classed and distributed, according to the degree of ex¬ 
actness with which we can compare them with works of 
art: thirdly, that the mechanical parts of our frame, or 
those in which this comparison is most complete, although 
constituting, probably, the coarsest portions of nature’s 
workmanship, are the most proper to be alleged as proofs 
and specimens of design. 
CHAPTER VIII. 
OF MECHANICAL ARRANGEMENT IN THE HUMAN FRAME 
We proceed, therefore, to propose certain examples ta¬ 
ken out of this class: making choice of such as, amongst 
those which have come to our knowledge, appear to be the 
most striking, and the best understood; but obliged, per¬ 
haps, to postpone both these recommendations to a third; 
that of the example being capable of explanation without 
plates, or figures, or technical language. 
OF THE BONES. 
I. I challenge any man to produce, in the joints and 
pivots of the most complicated or the most flexible ma¬ 
chine that was ever contrived, a construction more artifi- 
