I hold that the depravity of the physical and moral nature of man originated in his unnatural habits of life.  The origin of man, like that of the universe of which he is a part, is enveloped in impenetrable mystery.  His generations either had a beginning, or they had not.  The weight of evidence in favour of each of these suppositions seems tolerably equal; and it is perfectly unimportant to the present argument which is assumed.  The language spoken, however, by the mythology of nearly all religions seems to prove that at some distant period man forsook the path of nature, and sacrificed the purity and happiness of his being to unnatural appetites.  The date of this event seems to have also been that of some great change in the climates of the earth, with which it has an obvious correspondence.  The allegory of Adam and Eve eating of the tree of evil, and entailing upon their posterity the wrath of God and the loss of everlasting life, admits of no other explanation than the disease and crime that have flowed from unnatural diet.  Milton was so well aware of this that he makes Raphael thus exhibit to Adam the consequence of his disobedience:—­

Immediately a place
Before his eyes appeared, sad, noisome, dark;
A lazar-house it seemed; wherein were laid
Numbers of all diseased—­all maladies
Of ghastly spasm, or racking torture, qualms
Of heart-sick agony, all feverous kinds,
Convulsions, epilepsies, fierce catarrhs,
Intestine stone and ulcer, colic pangs,
Demoniac frenzy, moping melancholy,
And moon-struck madness, pining atrophy,
Marasmus, and wide-wasting pestilence,
Dropsies and asthmas, and joint-racking rheums.

And how many thousands more might not be added to this frightful catalogue!

The story of Prometheus is one likewise which, although universally admitted to be allegorical, has never been satisfactorily explained.  Prometheus stole fire from heaven, and was chained for this crime to Mount Caucasus, where a vulture continually devoured his liver, that grew to meet its hunger.  Hesiod says that, before the time of Prometheus, mankind were exempt from suffering; that they enjoyed a vigorous youth, and that death, when at length it came, approached like sleep, and gently closed their eyes.  Again, so general was this opinion that Horace, a poet of the Augustan age, writes:—­

Audax omnia perpeti,
Gens humana ruit per vetitum nefas;
Audax Iapeti genus
Ignem fraude mala gentibus intulit: 
Post ignem aetheria domo
Subductum, macies et nova febrium
Terris incubuit cohors,
Semotique prius tarda necessitas
Lethi corripuit gradum.