Several cases are reported by Dr. Abercrombie, and quoted by Professor Hyslop, in which mental impressions long since forgotten beyond the power of voluntary recall have been revived by the shock of accident or disease. "A man," he says, "mentioned by Mr. Abernethy, had been born in France, but had spent the greater part of his life in England, and, for many years, had entirely lost the habit of speaking French. But when under the care of Mr. Abernethy, on account of the effects of an injury to the head, he always spoke French.

"A similar case occurred in St. Thomas Hospital, of a man who was in a state of stupor in consequence of an injury to the head. On his partial recovery he spoke a language which nobody in the hospital understood but which was soon ascertained to be Welsh. It was then discovered that he had been thirty years absent from Wales, and, before the accident, had entirely forgotten his native language.

"A lady mentioned by Dr. Pritchard, when in a state of delirium, spoke a language which nobody about her understood, but which was afterward discovered to be Welsh. None of her friends could form any conception of the manner in which she had become acquainted with that language; but, after much inquiry, it was discovered that in her childhood she had a nurse, a native of a district on the coast of [Brittany, the dialect of which is closely analogous to Welsh. The lady at that time learned a good deal of this dialect but had entirely forgotten it for many years before this attack of fever."

Dr. Carpenter relates the following incident in his "Mental Physiology": "Several years ago, the Rev. S. Mansard, now rector of Bethnal Green, was doing clerical duty for a time at Hurst-monceaux, in Sussex; and while there he one day went over with a party of friends to Pevensey Castle, which he did not remember to have ever previously visited. As he approached the gateway he became conscious of a very vivid impression of having seen it before; and he 'seemed to himself to see' not only the gateway itself, but donkeys beneath the arch and people on top of it. His conviction that he must have visited the castle on some former occasion - although he had neither the slightest remembrance of such a visit nor any knowledge of having ever been in the neighborhood previously to his residence at Hurstmonceaux - made him inquire from his mother if she could throw any light on the matter. She at once informed him that being in that part of the country, when he was but eighteen months old, she had gone over with a large party and had taken him in the pannier of a donkey; that the elders of the party, having brought lunch with them, had eaten it on the roof of the gateway, where they would have been seen from below, whilst he had been left on the ground with the attendants and donkeys."

"An Italian gentleman," says Dr. Rush, of Philadelphia, "who died of yellow fever in New York, in the beginning of his illness spoke English, in the middle of it French, but on the day of his death only Italian."

Striking as these instances are, they are not unusual. Everyone on reflection can supply similar instances. Who among us has not at one time or another been impressed with a mysterious feeling of having at some time in the past gone through the identical experience which he is living now?

On such occasions the sense of familiarity is sometimes so persistent as to fill one with a strange feeling of the supernatural and to incline our minds to the belief in a reincarnation.

The "flash of inspiration" which, for the lawyer, solves a novel legal issue arising in the trial of a case, or, for the surgeon, sees him successfully through the emergencies of a delicate operation, has its origin in the forgotten learning of past experience and study.

Succeeding books in this Course will bring to light numerous other facts less commonly observed, drawn indeed from the study of abnormal mental states, indicating that we retain a great volume of sense-impressions of whose very recording we are at the time unaware. In other words, all the evidences point to the absolute totality of our retention of all sensory experiences. They indicate that every sense-impression you ever received, whether you actually perceived and were conscious of it or not, has been retained and preserved in your memory, and can be "brought to mind" when you understand the proper method of calling it into service.

A vast wealth of facts is stored in the treasure vaults of your mind, but there are certain inner compartments to which you have lost the combination.

The author of "Thoughts on Business" says: "It is a great day in a man's life when he truly begins to discover himself. The latent capacities of every man are greater than he realizes, and he may find them if he diligently seeks for them. A man may own a tract of land for many years without knowing its value. He may think of it as merely a pasture. But one day he discovers evidences of coal and finds a rich vein beneath his land. While mining and prospecting for coal he discovers deposits of granite. In boring for water he strikes oil. Later he discovers a vein of copper ore, and after that silver and gold. These things were there all the time - even when he thought of his land merely as a pasture. But they have a value only when they are discovered and utilized.

"Not every pasture contains deposits of silver and gold, neither oil nor granite, nor even coal. But beneath the surface of every man there must be, in the nature of things, a latent capacity greater than has yet been discovered. And one discovery must lead to another until the man finds the deep wealth of his own possibilities. History is full of the acts of men who discovered somewhat of their own capacity; but history has yet to record the man who fully discovered all that he might have been."

You who are a bit vain of your visits to other lands, your wide reading, your experience of men and things; you who secretly lament that so little of what you have seen and read remains with you, behold, your "acres of diamonds" are within you, needing but the mystic formula that shall reveal the treasure!