page 187, Psychology of the Unconscious, Practical Use of Dream Analysis;
“The gruesome character of the dreams is alone sufficient to make one pause. All the same, other people have anxiety dreams now and then. We must therefore look more closely into the meaning of the main symbols, “mother” and “horse”. They must be equivalents, for the best do the same thing: they commit suicide. “Mother” is an archetype and refers to the place of origin, to nature to that which passively creates, hence to substance and matter to materiality, the womb, the vegetative functions. It also means the unconscious, our natural and instinctive life, the physiological realm, the body in which we dwell or contained; for the "mother" is also the matrix, the hollow form, the vessel that carries and nourishes, and it thus stands psychologically for the foundations of consciousness. “