Note 13 — LIFE IN A TUB.1

The only true source of caloric in animals, is that produced by the chemical combination of oxygen with the carbon and other oxidizable products of their system. Every cause which quickens and exalts this chemical action increases the animal heat, whilst every interfering cause produces cold and chilliness. It is in this way that drinking cold water, or taking exercise in the open air, increases the warmth of the body, by producing a healthy13 waste of the system, and so stimulating the chemical combustion within it. Clothing, it should be recollected, has merely the effect of retaining animal heat and preventing its dissipation, but it cannot, in the slightest degree, create it: if, therefore, any thing occurs to interfere with that action, by which heat can alone be generated, all the clothes in the world will fail to warm us. How little these facts are reflected on, is shown by the excessive and injurious amount of clothing worn by delicate persons, which defeats the very object they are intended to effect. These facts also explain the apparent paradox of patients who, previous to undergoing the water system, complain of chilliness when smothered with clothing, but who afterwards are enabled to wear very light clothing, without any feeling of their former chilliness.14 On this subject Dr. Gully observes:—