Nothing is more important in the affairs of housekeeping than the choice of wholesome food. Apropos to this is an amusing conundrum which is as follows:--"A man went to market and bought _two_ fish. When he reached home he found they were the same as when he had bought them; yet there were _three!_ How was this?" The answer is--"He bought two mackerel, and one _smelt!_" Those who envy him his bargain need not care about the following rules; but to others they will be valuable: