facilitates the motion. Earth serves them for a basis, by giving
solidity to their texture: it is conveyed by air and water, which carry
it to those parts of the body with which it can combine. Fire itself,
disguised and enveloped under an infinity of forms, continually received
into the animal, procures him heat, continues him in life, renders him
capable of exercising his functions. The aliments, charged with these
various principles, entering into the stomach, re-establish the nervous
system, and restore, by their activity, and the elements which compose
them, the machine which begins to languish, to be depressed, by the loss
it has sustained. Forthwith the animal experiences a change in his whole
system; he has more energy, more activity; he feels more courage;
displays more gaiety; he acts, he moves, he thinks, after a different
manner; all his faculties are exercised with more ease. This igneous
matter, so congenial to generation--so restorative in its effect--so
necessary to life, was the JUPITER of the ancients: from all that has
preceded, it is clear, that what are called the elements, or primitive
parts of matter, variously combined, are, by the agency of motion,
continually united to, and assimilated with, the substance of animals--
that they visibly modify their being--have an evident influence over
their actions, that is to say, upon the motion they undergo, whether
visible or concealed.

The same elements, which under certain circumstances serve to nourish,
to strengthen, to maintain the animal, become, under others, the
principles of his weakness, the instruments of his dissolution--of his
death: they work his destruction, whenever they are not in that just
proportion which renders them proper to maintain his existence: thus,
when water becomes too abundant in the body of the animal, it enervates
him, it relaxes the fibres, and impedes the necessary action of the
other elements: thus, fire admitted in excess, excites in him disorderly