This book is an outdated bastion of ignorance, exposing the folly of establishing conjecture as fact until actual facts can be proven. As if that glaring deficiency wasn't apparent enough in this book, there are references throughout of "doctors," who, apparently experts on the subject, make up a good chunk of this book. No credentials are given for any of them, save Franz Mesmer and William James. Even with them though, the credentials are fleeting. Even doctors discredited earlier in the book are referenced again later, and Mesmer isn't the only one that falls into that category.
Some of the conclusions drawn are that hypnotized subjects are under some form of hysteria, and with some of the examples cited, it may have been the case. In fact, it was concluded that a subject would actually go into a hysterical fit under certain circumstances while under hypnosis, such as if they were instructed to do something against their morals. It seems like the subjects referenced in the parlor tricks disguised as scientific research clearly had something wrong with them before they ever got to the "doctor."
The book is not worth reading, unless you want to amuse yourself with the level of ignorance that "learned" men held at the time.
Stupidest quotes in the book:
A person who has nothing will give away any amount if told to do so; but quite different is the case of a wealthy merchant who really has money to sign away.
Really? A poor person would give away their last dime because it's only a dime? Really?
We know that hypnotism is akin to hysteria and other forms of insanity--it is, in short, a kind of experimental insanity.
Well, they're the experts...in more ways than they realized.