Dream is a second life. I have never been able to cross through those gates of ivory or horn which separate us from the invisible world without a sense of dread.
and writes a little further on (I found this passage so fascinatingly unusual that it actually made me giggle),
Meanwhile night was gradually falling and the sights, sounds and sensations of the place were becoming blurred to my slumbering mind. I thought I was sinking into an abyss which cut through the globe. I felt myself being buoyed along by a current of molten metal; a thousand similar streams whose hues varied with their chemical compositions were criss-crossing the earth like the vessels or veins that wind through the lobes of the brain. From the pulse and flux of their circulation, I gathered these streams were made up of living beings in a molecular state, which only the speed at which I was traveling made it impossible to distinguish. A whitish light was filtering into these channels, and at last I saw a new horizon open up like a huge dome dotted with islands washed by luminous waves. I found myself on a coast lit by a light not of the sun and saw an old man who was cultivating the soil. I recognized him as the same man who had spoken to me through the voice of the bird, and whether it was his words or my inner intuition of them, it became evident to me that our ancestors assumed the shape of certain animals in order to visit us on earth and take part in the various phases of our existence as silent observers.
Translated by Richard Sieburth for Penguin Classics