However, as a matter of practical fact, the "mechanic" has his limitations, like the normal consciousness. He is not omnipotent. Consequently we cannot be sure of being able to stimulate him to the extent of a cure. It depends on his knowledge and power. But he can always do something, if we can get at him. The chief difficulty is that in many people he is inaccessible. For instance, I have many times submitted myself to the treatment of Dr Tuckey and another medical friend, without effect. I have each time tried my best to help, making my mind as passive as I could; for I was sure that if a suggestible stage could be reached, some troublesome heart symptoms and insomnia could be alleviated. But I was never able to reach a state even approaching hypnosis. I suppose my normal consciousness could not put itself sufficiently to sleep. Being interested in the scientific aspect of the subject, my consciousness watched the process and analysed its own sensations, instead of "letting go" and subsiding out of the way. As to the proportion of susceptible persons, observers differ. Wetterstrand and Vogt hold that all sane and healthy people are hypnotisable, and Dr Bramwell's results among strong farm labourers at Goole support that view. Patients with nervous ailments are difficult to hypnotise; out of one hundred such cases in his London practice, Dr Bramwell only influenced eighty. This is the percentage of susceptibles found by Drs Tuckey and Bernheim also. The insane are usually unhypnotisable, probably because of their inability to concentrate their attention. Out of the 80 per cent. of sane susceptibles, only a small proportion go off into hypnotic sleep; ten according to Tuckey, rather more according to the experience of Bramwell, Forel, and Vogt. Most of the susceptible, however, though retaining consciousness, may be deprived of muscular control. For example, if told that they cannot open their eyes, they find that it is so. The various "stages" of hypnosis shade gradually into each other, and classifications are not much good. Charcot's three stages of lethargy, catalepsy, and somnambulism are now discredited as true stages. In good subjects they are producible at will, and as observed at the Salpêtrière they were almost certainly due to training. I have no space for the quoting of detailed medical cases, but it is desirable to emphasise the practical facts and to make the subject as concrete as possible to the reader, so I will quote just one, as illustration, from Dr Bramwell's contribution to _Proceedings of the Society for Psychical Research_, vol. xiv, page 99.