This story comes from an article on waking hypnosis. An army doctor is telling the story and it illustrates perfectly how powerful the mind is:
“During World War II, I worked as an anaesthetist in a station where casualties were brought in after battle. I was working with nitrous oxide and the day had been a very busy and tiring one. I noticed that the nitrous oxide tank was getting low but later, in the excitement, I failed to noticed that it was completely used up. When I finally realised this, I drew the surgeon aside and said ‘My God, that nitrous tank must have been empty for the past hour or so. What are we going to do?’
The surgeon answered, ‘There is nothing we can do now. We will have to keep on working just as we have been. These men have been getting perfect anaesthesia. They think they are anaesthetised, and consequently they are. Keep on doing what you are doing and don’t say a word.'”
How powerful the mind is!