My numerous other duties have, unfortunately, delayed the appearance of this edition of my book, in spite of the fact that the third has long been sold out. In the present, fourth edition, I have completely revised my former work and made many important additions thereto. I have endeavoured to bring it into line with our present-day knowledge, and have laid special stress on the universal importance which has become attached to hypnotism and suggestion during the last ten years. I have given the narrowest limits possible to the concept suggestion, with the view of better differentiating suggestion from other psychic process than was formerly done. Relatively speaking, the fewest alterations have been made in the chapters on symptomatology and post-hypnotic suggestion. Very little has been added to our knowledge of these questions during the last few years, and it would appear that this branch of hypnotic research is fairly exhausted, though, of course, it may one day happen that it will have to go through a searching revision which will prove instructive.

In the chapters which treat of the various theories of hypnotism I have endeavoured to throw fresh light on the experiments I originally made for the purpose of explaining the phenomena. But I adhere to the position I primarily assumed - to wit, that certain premises must be accepted if we are to explain hypnotism. We shall be far more likely to arrive at a proper conception of hypnosis by reasoning from analogy than by paying any attention to misty psychological concepts or physiological experiments which our present knowledge of ultimate cerebral processes is quite unable to explain. I have added a chapter dealing with the general influence that hypnotism and suggestion have had on medicine: thefirst part of it is devoted to theoretical medicine and the far-reaching effects of hypnotism on this branch of the question; the second part contains a study of the salient points of psycho-therapeutics. I have done this because psycho-therapeutics seems to me to be a developmental outcome of hypnotic and suggestive therapy, and ought, therefore, to be distinguished from hypnotic therapeutics, which only constitutes a small branch of general psycho-thera-peusis. Attention is also drawn to the connection that subsists between hypnotism and the science of psychology, especially with regard to the important part played by suggestion in all psychological investigations.

I have also discussed the influence of suggestion on other questions, such as art, superstition, ethnology, etc., much more fully than in the earlier editions of this work. My reason for doing this is the tendency nowadays to overlook the influence of modern hypnotism on the most varied branches of science and the different phenomena they present. The revised chapter on the legal aspect of hypnotism will be found to contain much fuller details than in former editions. I have shown in it the close historical connection that subsists between the psychology of testimony and hypnotism. The last section of the book - that dealing with the most important points connected with occultism - has been considerably enlarged. I felt bound to extend this chapter: first of all, because hypnotism has brought to light many sources of error in this connection, and secondly, because real criticism affords us the best means of stemming the tide of the uncritical advocacy of occultism. It cannot be denied that belief in occultism has increased in recent times. I do not assume this merely from the increase in the number of occultistic societies and periodicals, but rather because private conversation has convinced me of the fact.

I have also observed an increased tendency on the part of the public to mystery-mongering. I need only recall the epidemic of "faith-healing," the sensation caused by the so-called "sleep-dancers," the way in which many people were upset by the doings of the horse " Clever Hans," the uncritical praise bestowed on the divining-rod, and the medical miracles of such individuals as Kneipp, etc., etc. The fact that so many worthy men of science have taken to this mystery-mongering is not calculated to make future generations have much respect for the present age. That a man like Crookes should believe that Home could overcome the force of gravity without employing any mechanical means, that Lom-broso should believe that Eusapia Palladino could move objects by the action of her will alone, that Stumpf should believe that a horse could be educated like a child and be influenced by telepathy, that Richet should believe that the murder of the Servian royal family was foretold in Paris by occult means - all these things are but instances of the errors that otherwise competent investigators may make.

For they are nothing but cases of error, not because the investigators attempted to explain the impossible, but because they based their conclusions on imperfect data, and did not see the pitfalls before them. These scientists and others like them, prove that a man may be proficient in his own special branch and yet quite incapable of criticizing other methods of research. In spite of these and other authors who express a belief in occultism and spiritism, I can safely say, not only as the result of my own experiments but also from a careful study of numerous occultistic and spiritistic works, that I have never come across even one single experiment carried out under strictly scientific conditions that could be said to justify the assumption that occult forces exist. One of the biggest swindles perpetrated by occultists is the way in which they promise beforehand strict adherence to scientific conditions, and then do their utmost to prevent such conditions being observed.

In spite of my most earnest endeavours, I have never been able to detect even the slightest approach to occult phenomena, provided strict conditions were observed; in all these investigations the assumption of animal magnetism, telepathy, clairvoyance, etc., was altogether superfluous. I am, of course, just as willing in the future as I always have been in the past to investigate, under the conditions enjoined by science, all cases of mediums, magnetizers, etc., etc., who profess to possess occult powers, for I consider a priori negation just as unscientific as those swindles and frauds connected with occultism which I have so strongly condemned.

ALBERT MOLL.

St. Helier, Jersey.