The term “incubation” in its rigid sense applies to the act of hatching eggs, either naturally or artificially. It has however been adopted by physicians to denote that state of predisposition to disease, in which the germ of the malady lurks, latent and unperceived by the inexperienced observer. Too frequently the individual who is thus menaced is totally unaware of his condition. So far from being depressed in spirits, his hopes are more sanguine, and his future projects more industriously formed than usual. At other times, on the contrary, he labours under a load of despondency which he cannot explain, and his gloom seems to anticipate his end. This presentiment has oftentimes been singularly prophetic. Moreau de St. Remy relates the case of one of his most intimate friends, who visited him, saying, “I come to die near you.” He was apparently in perfect health, but the prediction too soon proved true.

It is no doubt probable, that in these cases the influence of the mind labouring under these fatal impressions brings about, by its all-powerful sympathetic power on our functions, the expected yet dreaded event.

Incubation is observed in many contagious affections; and in hydrophobia its duration is amazing, this dreadful malady developing itself years after the original accident. In mental diseases, aberrations of the intellectual faculties are noticed long before the patient can be pronounced insane; oddities, as they are called, are frequently the precursors of mania.

The ancient Greeks and Egyptians use the term “incubation” in another sense. With them it expressed the religious ceremony of sleeping in the temples of the gods, to be inspired with the means of relieving their sufferings. Nothing can express this superstitious rite more forcibly than the following letter from Aspasia to Pericles, recorded by one of the scholiasts of Ælian.

“Aspasia to Pericles, greeting. Podalirius! Podalirius, to whom Love taught the art of healing, and who in return didst consecrate thine art to Love, I return thee my thanks. Athens will once more see me beauteous! I shall have lost none of my attractions, and Pericles shall find in his Aspasia all that he once held dear! Podalirius, I return thee my thanks; and thou, Pericles, be grateful to my benefactor. I did not wish to write to thee until I was certain that I had been cured. I shall relate to thee my voyage. I punctually followed the instructions of Nocrates, that wise and enlightened physician. I first repaired to Memphis, where I visited, but without success, the temple of Isis. I there beheld the goddess, and her son Orus, seated on a throne, supported by two lions. The Sebestus[23] grew round her shrine! Incense was burnt in the morning, myrrha during the day, and cyplis at eve. I was assured that young Alexander had come to this temple not long before to indulge in a holy contemplation, and learn by inspiration the means of curing his friend Ptolemy: his supplications were heeded. I also slept in the temple, but found no relief. This misfortune, alas! was attributed to my incredulity. I took my departure, and repaired to Patras. There I saw in her temple the divine Hygeia; not as she was represented by Aristophanes, when she relieved Plutus, sweet and graceful, clothed in an aerial robe and a short tunic, and holding in her hand a cup of Musa, whence a serpent was seen to spring, but she appeared to me in the form of a mysterious pentagon. I first paid a devout visit to the fountain; and while I deposited my offerings at the feet of the goddess, a mirror was floating on the surface of the waters upon which I gazed by order of the priests, but I was not cured! Thence I went to sleep at Pergania and at Hercyna. But the gods seemed to slumber when Aspasia slept! On a sudden the name of Podalirius struck mine ear! I was informed that his temple was at Lacera. I instantly sought it; and, on my arrival, bathed in the Althonus. After the bath, I was anointed with the perfumed balsams that our friend Sosinius had given me in the temple of Mercury the day I left Athens. I then put up my prayers to deserve the favour I implored from the god. At nightfall I sought repose on the skin of a ram close to the statuary pillar. I soon found myself in that state when we are no longer wide awake, but when sleep has not yet lulled our senses to repose. Methought that a celestial light was shed around me. Æsculapius appeared to me with his two daughters; and, from the clouds that surrounded him, he promised me my pristine health. I soon after fell into a profound sleep; but towards the break of day I beheld Cypris—Cypris who was always the friend of Podalirius: she came herself! I recognised her, although she had assumed the form of a gentle dove. Yes, Cypris came to cure me. Podalirius! Æsculapius! Cypris! each day shall you be thanked by Aspasia and by Pericles.

“I must now relate to thee the vision of a Daunian, who slept near me. She suffered from an affection of her breast, and this she dreamed:—She beheld the young god Harpocrates lying on leaves of lotos, and covered with bandages from the head to the feet. He appeared weak and emaciated; he cried like an infant, supplicating the poor woman to nurse him. Soon after, she dreamt that a lamb came to seek his sustenance from her bosom. The dream was fulfilled,—it clearly indicated the use of a certain plant; but, until it could be obtained, the Daunian was advised to eat nothing but stewed raisins. Learn that here various names are given to various inspirations. The last dream I have related is called allegorical. When a dream prescribes a certain remedy, it is named theÔrematic. Here are many dreams: wise Pericles, thou art perhaps smiling at them; but what is not visionary is my perfect recovery, and my love for thee. Farewell!”

Although this letter of Aspasia is an evident fiction, yet it gives an excellent, though a romantic description of the incubation of the ancients. Aspasia was supposed to be labouring under one of the most vexatious disorders that can affect a pretty woman,—an eruption in the face; hence the gods sent her a mirror, that her devotion might be increased by her unsightly appearance. It is not improbable that in those days, as in the present era, women of a certain, or rather an uncertain age, were more fervid in their endeavours to render themselves acceptable to Heaven when they ceased to be admired and sought for upon earth.