The present thesis is chiefly concerned with disturbances during recovery from anaesthesia. This area has been poorly studied. Medicine has tended to leave the patient's well-being during the period of wrecoveryM to the powers of nature. At one time~ anaesthetists considered anaesthesia as a good surrogate for sleep. It has proved to be notoriously difficult to eradicate this simplicism because it offers a readily understandable, if misleading, explanation of the action of anaesthetic agents. Such thinking is even perpetuated in the standard pharmacological vocabulary. For example, it is known that no drug or technique we still promise has been found to induce a state of natural sleep~ yet talk about "hypnotics". Ought an anaesthetist~ then to his patient that anaesthesia will be "just like a pleasant sleep"? It is doubtful to what extent contemporary anaesthesia, That erroneously likened to invigorating sleep, is really safe. most illustrious anaesthesiological professional society, the Association of Anaesthetists of Great Britain and Ireland~ displays a noble coat of arms with the motto "In somno securitas". There are occasions when one is inclined to put a question mark after this statement. Fortunately, it is understood nowadays that a good anaesthetic should be less of a pharmacological manipulation tenance of which depresses vital functions and more of a mainnonnill physiological functions in terms of optimal body homeostasis. In other words, an anaesthetic based on preserving, restoring will probably more classical "borrow'd and supporting the functioning of the body closely resemble a pleasant sleep than the likeness of shrunk death" (Shakespeare~ Romeo & Juliet, Act IV, Scene 2~ line 104).