Dr. Creighton insists chiefly on the importance of change, which—­ though I did not notice his saying so—­he would doubtless see as a mode of cross-fertilisation, fraught in all respects with the same advantages as this, and requiring the same precautions against abuse; he would not, however, I am sure, deny that there could be no fertility of good results if too wide a cross were attempted, so that I may claim the weight of his authority as supporting both the theory of an unconscious memory in general, and the particular application of it to medicine which I had ventured to suggest.

“Has the word ‘memory,’” he asks, “a real application to unconscious organic phenomena, or do we use it outside its ancient limits only in a figure of speech?”

“If I had thought,” he continues later, “that unconscious memory was no more than a metaphor, and the detailed application of it to these various forms of disease merely allegorical, I should still have judged it not unprofitable to represent a somewhat hackneyed class of maladies in the light of a parable.  None of our faculties is more familiar to us in its workings than the memory, and there is hardly any force or power in nature which every one knows so well as the force of habit.  To say that a neurotic subject is like a person with a retentive memory, or that a diathesis gradually acquired is like an over-mastering habit, is at all events to make comparisons with things that we all understand.

“For reasons given chiefly in the first chapter, I conclude that retentiveness, with reproduction, is a single undivided faculty throughout the whole of our life, whether mental or bodily, conscious or unconscious; and I claim the description of a certain class of maladies according to the phraseology of memory and habit as a real description and not a figurative.” (p. 2.)

As a natural consequence of the foregoing he regards “alterative action” as “habit-breaking action.”

As regards the organism’s being guided throughout its development to maturity by an unconscious memory, Dr. Creighton says that “Professor Bain calls reproduction the acme of organic complication.”  “I should prefer to say,” he adds, “the acme of organic implication; for the reason that the sperm and germ elements are perfectly simple, having nothing in their form or structure to show for the marvellous potentialities within them.

“I now come to the application of these considerations to the doctrine of unconscious memory.  If generation is the acme of organic implicitness, what is its correlative in nature, what is the acme of organic explicitness?  Obviously the fine flower of consciousness.  Generation is implicit memory, consciousness is explicit memory; generation is potential memory, consciousness is actual memory.”

I am not sure that I understand the preceding paragraph as clearly as I should wish, but having quoted enough to perhaps induce the reader to turn to Dr. Creighton’s book, I will proceed to the subject indicated in my title.