It is not true, as many claim, that the subject's body can be made to resist the destruction of heat, cold, blows, injuries, etc., while under hypnotic influence. He can be rendered insensible to the impressions produced by these things, but he cannot be rendered proof against their actual effects. It is cruelty to command a subject to pick up a live coal. He may do it without suffering at the time, if the suggestion is given that it will not burn, but the coal will nevertheless burn his flesh.

A subject might be induced to stare with wide open eyes at the glaring sun and he might obey without manifesting any discomfort, but blindness would certainly result, for which the hypnotist would be responsible.

It is also inadvisable to change suddenly from darkness to brightness or from brightness to darkness without first warning the subject by such words as: "Now, it is going to get very light," etc. remove the object of fascination without stating that you are about to do so, the shock might otherwise injure him.

Injuries may be received during the hypnotic state, which may cause the death of the subject or cripple him for life. It is true that hypnotized persons and somnambulists can often walk in dangerous places without falling, because they do not realize their danger and consequently do not lose their presence of mind. But if such persons should walk upon frail supports, their hypnotized state would not keep the supports from breaking, neither would it lessen the danger of walking on slippery places.

It is a common practice for hypnotists during an exhibition to make the subjects jump and leap and contort their bodies. This is all well, provided that care is taken to watch each one carefully so as not to permit any action that might strain the muscles or cause rupture or any other injury. Moderation is always best. It may be remarked that "they know enough not to hurt themselves." This is not true, for their whole mind is occupied in carrying out the suggestion, and does not take the least concern for personal safety. Violent exercise loses none of its injurious effects upon a hypnotized person.

Some of the most interesting experiments may be made by suggesting that harsh articles, such as nails, stones, etc., are articles of food, and directing that they should be eaten. This is always an indiscretion and liable to cause trouble. The suggestion of eating implies swallowing, and to swallow such articles means danger. Care must be taken, also, not to allow the mouth to be filled with powders, paper, or other substances that might cause strangulation when swallowed or inhaled. Such accidents are rare, because hypnotists are usually cautious about these things. Attention is here called to them for the purpose of making assurance doubly sure.

It is well known that while under the hypnotic influence, subjects can eat most obnoxious articles without realizing their unpleasant effects, provide the proper suggestions are made. It is possible to give a subject a glass of diluted ammonia and say: "Here, drink this glass of milk," and thus get him to drink it. But such an act would be grossly wrong, for the ammonia would injure the throat and stomach, even though it were not strong enough to cause strangulation and even though he experienced under suggestion, a pleasurable sensation while swallowing it.