Like the brain, the spinal cord has its memory. A spinal cord without memory would be an idiotic spinal cord…

Henry Maudsley, Physiology and Pathology of Mind (1867)

The unconscious will in the self-standing spinal cord.

Eduard von Hartmann, Philosophie des Unbewussten (1869)

Many forms of fish, bird and beast

Brought forth an Infant form

Where was a worm before

William Blake, The First Book of Urizen (1794)

[F]irst we are a rude masse, and in the ranke of creatures, which only are; next we live the life of plants, the life of animals, [and] the life of men […] Thus is man that great and true Amphibium, whose nature is disposed to live, not onely like other creatures in divers elements, but in divided and distinguished worlds […] Thus we are men, and we know not how; there is something in us that can be without us, and will be after us, though it is strange that it hath no history what it was before us, nor cannot tell how it entered in us.

Thomas Browne, Religio Medici (1642)