It is well known that people who indulge in alcohol show less resistance to infectious diseases than abstemious individuals. The paralysis of the white blood-corpuscles is one of the strong arguments against the use of alcohol. The experience of life insurance companies in England and America has clearly shown that even the "moderate" use of alcoholic beverages shortens human life. (See "Alcohol" in SUPPLEMENTARY NOTES.) Dr. Stockard has also shown in mice, on which he has experimented, that the effect of alcohol on the germ-plasm is distinctly injurious. It is a fair inference that the use of alcohol by parents tends to damage their offspring. [Sidenote: Tobacco] The evils of tobacco have not been so much studied and are not so well understood as those of alcohol. But every athletic trainer observes that the use of tobacco lessens physical fitness. The ordinary smoker is unconscious of this and often denies it. He sometimes says, "I'll stop smoking when I find it hurting me; it doesn't hurt me now." The delusive impression that one is well may continue long after something has been lost from the fitness of the body, just as the teeth do not ache until the decay has gone far enough to reach the nerve. At Yale and at Amherst it has been found, by actual measurement, that students not using tobacco during the college course had gained over the users of tobacco in weight, height, growth of chest, and lung capacity. Prof. Pack, of the University of Utah, finds that tobacco-using athletes are distinctly inferior to those who abstain. Prof. Lombard, of the University of Michigan, finds that tobacco lessens the power of the voluntary muscles, presumably because of the depressing effect on the central nervous system. There is also much experimental evidence to show that tobacco in animals induces arterial changes. The present well-marked upward trend of mortality from diseases of the arteries offers a good reason for heeding such evidence and taking the safe side in every controversy regarding it. (See "Tobacco" in SUPPLEMENTARY NOTES.) [Sidenote: Germs] The poisons so far mentioned are limited to the amounts taken. Infections with germs, however, bring in poisons, the quantities of which tend to increase with the multiplication of the germs. It is, therefore, especially important to avoid infections. We should not depend altogether on the protection of our health officers. We must guard our own individual bodies. [Sidenote: Colds and La Grippe Germs] Infections enter the body through the skin or mucous lining. The common cold is believed to enter by the nose. We may avoid exposure to infection from grippe and common colds by keeping away from congested public places when there is an epidemic of grippe or colds, or when we are ourselves fatigued or for any reason likely to catch cold.