To judge, then, the influence of rainfall on health, we require three data--the total rainfall, the number of rainy days, and the aspect of the sky in any given season of the year; for the beneficent influence of light on the animal organisation is at least as marked as it is on plants, though while the latter fact is a matter of common observation, the former does not meet with the recognition which it deserves. We bleach our celery by protecting it from the light, but are apt to forget that, while the consequent reduction in the amount of its characteristic essential oil makes its eatable, the plant could hardly survive but for the application of lime and other artificial antiseptics, which we are obliged to apply to make up for the lack of the natural protection. Whether the process of “earthing up” be soothing to a celery plant or otherwise is a question of which we have no means of judging, but there can be no doubt that in such matters man is far more practical in the treatment of plants than of himself, and that in tropical climates he often suffers by shrinking too much from the immediate effects of the sun’s rays. In this as in all other affairs, moderation is, of course, desirable, but the commoner mistake is undoubtedly to shirk too much all exposure to the sun, whereas those whose avocations take them most into the open are generally the healthiest in the Tropics as elsewhere. Contrast the ardent sportsman who spends the broiling days of May and June in the pursuit of large game, with the lady who spends her days in a darkened bungalow, and there can be no question as to which suffers the most from “the effects of climate”; nor is the difference, as is often suggested, purely one of sex, for it will be noticed that female medical practitioners and missionaries and other ladies whose occupations involve their being much in the open are commonly at least as healthy as men similarly situated. In all hot countries the period of the rains is the sickly season, but this is due not so much to any direct evil effects of damp on the human system as to the fact that the agents and carriers of disease, i.e., low plant organisms and mosquitoes and other suctorial insects, find in heat moisture and puddles the conditions that best favour their growth and multiplication; in other words, the unhealthiness of this season can be largely obviated by suitable measures of sanitation, so designed as to impede this growth and multiplication of noxious agencies in the immediate vicinity of human habitations.