The science of neuroendocrinology — the brain-to-pituitary link that was discerned by [Joe] Hinsey, [George] Wislocki, du Vigneaud, and [Geoffrey] Harris—is dependent upon hormones flowing within nerve axons. This phenomenon, axonal flow, was first noted by Ernst and Barta Scharrer... For many decades it was assumed that axonal flow was always 'down'... away from the brain.

The Fabric of Mind (1985)