Page:Popular Science Monthly Volume 23.djvu/503

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would be utterly inexplicable without the analogies of the post hoc ergo propter hoc fallacy—our liability to mistake a coincidence for a causal connection. In cold weather the hyperborean biped retreats to his unventilated den and contracts a catarrh, which he ascribes, not to its true cause, foul air, but to cold air, having noticed that winter and pulmonary affections are annual concomitants. Fruits, like countless other products of nature, are most abundant when they are most needed, and have for ages preserved the health of our tropical ancestors; but their carnivorous descendant ascribes his affliction, not to his daily beefsteaks, but to the occasional peaches and watermelons of which he happened to partake about the time the fever took hold of him. At the end of the year, when fruits become scarce, fevers too disappear, and the proof seems complete. Inductive logic: but the precipitate follower of Viscount Verulam fails to explain the fact that in the swampiest and hottest districts of the Eastern Continent fevers and fruits exclude each other like science and superstition, and the still stranger fact that hundreds of Northlanders who scrupulously abstain from fruit are nevertheless victimized whenever they brave the sun of the lower latitudes. In cholera the fruit-delusion may have derived a color of plausibility from the circumstance that persons who have for months subsisted upon beef and farinaceous food are liable to an attack of diarrhoea after their first experiments with a more digestible diet. For analogous reasons a long incarceration makes a prisoner unable to bear the fresh air and clear light of the outer world. The Creoles use pepper enough with their meat to dispense with other antiseptics, and yet eat fruit with every meal as the French serve a dessert of cakes and raisins—"pour la bonne bouche." A dime's worth per day for every man, woman, and child, of such fruits as oranges, melons, or "Chickasaw plums," that can be bought in almost every Southern town, would soon ruin the business of the quinine-manufacturers and reduce the trade of the "bitters" distillers to customers who like to drink whisky under some more respectable name.

The Spaniards divide all articles of diet into comidas frias and comidas calientes; but their definition of calorific food does not quite coincide with Liebig's theory.[1] According to the nitrogenous and non-nitrogenous system, starch, sugar, gums, are "respiratory" food, and as exclusively heat-making as fat, while the experience-taught South American would unhesitatingly class starchy potatoes and starchy corn-bread with the comidas frias, the "cooling comestibles"; and flesh, eggs, and rich cheese with the heat-producers. Cold milk would be assigned to the former class, and, together with unleavened and

  1. Professor Draper ("Human Physiology," p. 27) warns us that Liebig's classification has been only "adopted for the sake of convenience," having no natural foundation. Funke, in his "Lehrbuch der Physiologie," p. 186, accepts it with considerable reservations. Verdeil, Robin, Mulder, and Moleschott, reject it as wholly untenable.