It is not enough that the individual should know how to live. Knowledge is of no avail without practise. Mr. Moody, the evangelist, once said of religious conversion, "Merely to know is not to be converted. I once boarded a train going in the wrong direction. Some one told me my mistake. I then had knowledge, but I did not have 'conversion' until I acted on that knowledge--seized my traveling-bag, got off that train, and boarded one going in the opposite direction." Many people are on the wrong train in hygiene, as in religion, and know it. They are traveling fast to that kind of perdition which in the end unhygienic living always brings. In fact, a great many people practise unhygienic habits more through indifference than through ignorance. Most people have acquired, by imitation of their neighbors, a great number of unhygienic habits and have continued in these habits for so many years, that they can not get rid of them, except through a great effort of will. This effort they are usually unable or unwilling to put forth unless very strong incentives are brought to bear. Often--in fact, if the truth were known, usually--they wait until ill health supplies the incentive. The man who is most receptive on the subject of health conservation, is, in the majority of cases, the man who has just had some ominous warning of coming ill health; although there is now a small but increasing number who do not wait so long, men who pride themselves on keeping "in the pink of condition." These are the men who are rewarded for their efforts by enjoying the highest reaches of working-power. [Sidenote: Cost of Good Health] The ordinary man, in ordinary good health, does not want or thinks he does not want to live hygienically. He sees all sorts of imaginary objections to adopting a hygienic life, and closes his eyes to its real and great advantages. One of the objections often trumped up is that the practise of hygiene costs too much--that it can only be a luxury of the rich. It is quite true that here, as elsewhere in human life, wealth confers great advantages. The death-rate among the rich is always less than that among the poor. And yet the rich have unhygienic temptations of their own, while the poor, on their part, are far from living up to their opportunities. [Sidenote: Missionaries]