The only class of pathological cases which seem peculiarly open to the hypnotic influence is that of the hystero-epileptics, whose tendencies are toward extreme suggestibility.
Further, one may hypnotize himself--what we have called above Auto-suggestion--especially after having been put into the trance more than once by others.

When let alone after being hypnotized, the patient usually passes into a normal sleep and wakes naturally.
It is further evident that frequent hypnotization is very damaging if done by the same operator, since then the patient contracts a habit of responding to the same class of suggestions; and this may influence his normal life.

A further danger arises from the possibility that all suggestions have not been removed from the patient's mind before his awaking.

Competent scientific observers always make it a point to do this.

It is possible also that damaging effects result directly to a man from frequent hypnotizing; and this is in some degree probable, simply from the fact that, while it lasts, the state is abnormal.
Consequently, all general exhibitions in public, as well as all individual hypnotizing by amateurs, should be prohibited by law, and the whole practical application as well as observation of Hypnosis should be left in the hands of physicians or experts who have proved their fitness by an examination and secured a certificate of licence.
In Russia a decree (summer, 1893) permits physicians to practise hypnotism for purposes of cure under official certificates.