Of the diseases caused by bad habits, it can only be said that all the evils they cause, directly and indirectly, are entirely preventable; that they are usually wrong morally, and that the suffering which results is sure. Under this head come the effects of drinking, of the use of tobacco and drugs, and of bad personal and social habits. It is only necessary to refrain from these bad habits to prevent all the diseases that arise from them, with all their train of suffering, poverty and crime. It is not the province of this book to deal with scientific temperance, but merely to state a few of the most serious results of the use of alcohol and other poisons. The white corpuscles of the blood have been called our "standing army," because they are natural germ-destroyers. One class of the white cells has the power of motion, and another class has the power of absorbing outside matter, such as disease-germs. One destroys the germs and the other moves them through the blood and carries them off with the waste products of the body. The white corpuscles thus stand as the defenders of the body, ready to destroy the germs as they enter, and are, for each individual, the best of all preventives of germ diseases. The person whose blood is lacking in white cells is always liable to "catch" contagious or infectious diseases, and the one who has that element of the blood in proper proportion is best fitted to withstand disease. Leading physicians believe that the greatest harm that comes from the use of alcohol lies in the fact that nothing else so weakens the resistance of the white corpuscles, and that therefore the person who is an habitual user of alcohol lacks the power to repel all classes of disease. English and American life insurance companies give us almost exactly the same figures, which show that of insured persons, the death rate is twenty-three per cent. higher among those who use alcohol than among total abstainers. It is probable that the proportion of persons carrying life insurance is much less among the drinking classes and that if we had complete statistics the difference would be far greater than appears in the life insurance tables. Of time lost by sickness, directly and through other diseases caused by alcoholism, drugs and other bad habits, the percentage is very great, according to all hospital records. The number of prominent persons who have died of "tobacco heart" indicates that the rate of those whose heart action is weakened by the use of tobacco is probably very large. Doctor Morrow says that if we could put an end at once to diseases caused by bad habits it would result in closing at least one-half of our institutions for defective persons, and almost all of our penal institutions.