Today, 1974, in large medical centers, evaluation of the patient in coma is almost a daily necessity, and the need to evaluate the patient in deep coma arises once or twice every week. Even in smaller hospitals the problem is not uncommon. This has come about because many laymen and most medical personnel are now well trained in methods of cardiorespiratory resuscitation. Persons are not allowed to die easily and once resuscitated, are moved to intensive care units where life is maintained. Fortunately, if they do not die of their underlying disease, such as trauma or myocardial infarction, many patients thus rescued recover completely; that more do not is due to the fact that the brain is such a tender organ--only a few minutes without oxygen and neurons die or are damaged--only a short while without blood flow and, apparently, the cerebral blood does not flow again. On the other hand, neurons, silenced completely by drugs for hours or even days, may recover and soon be alive and well
