For those who study the great art of lying in bed there is one emphatic caution to be added. Even for those who cannot do their work in bed (as, for example, the professional harpooners of whales), it is obvious that the indulgence must be very occasional. But that is not the caution I mean. The caution is this: if you do lie in bed, be sure you do it without any reason or justification at all. I do not speak, of course, of the seriously sick. But if a healthy man lies in bed, let him do it without a rag of excuse; then he will get up a healthy man. If he does it for some secondary hygienic reason, if he has some scientific explanation, he may get up a hypochondriac.