AND FUNCTIONS OF ANIMALS, &C. 
49 
ply itself, and you will confess it to be entitled to a name, 
which it has sometimes received, that of “the chemical 
wonder of animal nature.” 
Still we are ignorant of the composition of this fluid, and 
of the mode of its action; by which is meant, that we are 
not capable, as we are in the mechanical part of our frame, 
of collating it with the operations of art. And this I call 
the imperfection of our chemistry; for should the time ev¬ 
er arrive, which is not perhaps to be despaired of, when we 
can compound ingredients, so as to form a solvent which 
will act in the manner in which the gastric juice acts, we 
may be able to ascertain the chemical principles upon 
which its efficacy depends, as well as from what part, and 
by what concoction, in the human body, these principles 
are generated and derived. 
In the meantime, ought that, which is in truth the de¬ 
fect of our chemistry, to hinder us from acquiescing in the 
inference, which a production of nature, by its place, its 
properties, its action, its surprising efficacy, its invaluable 
use, authorises us to draw in respect of a creative design? 
Another most subtile and curious function of animal bod¬ 
ies is secretion. This function is semi-chemical and semi¬ 
mechanical; exceedingly important and diversified in its 
effects, but obscure in its process and in its apparatus. 
The importance of the secretory organs is but too well at¬ 
tested by the diseases, which an excessive, a deficient, ora 
vitiated secretion is almost sure of producing. A single 
secretion being wrong, is enough to make life miserable, 
or sometimes to destroy it. Nor is the variety less than 
the importance. From one and the same blood ( I speak 
of the human body) about twenty different fluids are sepa¬ 
rated; in their sensible properties, in taste, smell, color, 
and consistency, the most unlike one another that is possi¬ 
ble; thick, thin, salt, bitter, sweet: and, if from our own 
we pass to other species of animals, we find amongst their 
secretions not only the most various, but the most opposite 
properties; the most nutritious aliment, the deadliest poi¬ 
son; the sweetest perfumes, the most fetid odors. Of 
these the greater part, as the gastric juice, the saliva, the 
bile, the slippery mucilage which lubricates the joints, the 
tears which moisten the eye, the wax which defends the 
ear, are, after they are secreted, made use of in the animal 
economy; are evidently subservient, and are actually con¬ 
tributing to the utilites of the animal itself. Other fluids 
seem to be separated only to be rejected. That this also 
is necessary (though why it was originally necessary, we 
E 
