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255) [[left margin]] On the Effect of heat & cold upon the animal body. [[/margin]] The effects of heat and cold may be considered here with respect to their action on the nervous, sanguineous, and glandular systems. Dr. Fal [[strikethrough]] oner's [[/strikethrough]] ^ [[insertion]] coner's [[/insertion]] remarks on the influence of Climates, &c. 4[[superscript]] th [[/superscript]]. 1781. - Book I. Chap. I. p. 3. [[left margin]] On the effect of heat upon the living human body. [[/margin]] Heats is perhaps the most universal stimulus with which we are acquainted; when applied to any great degree to the human body, it excites the action of the nervous system in general, and of the cutaneous nerves especially, which are most exposed to its influence, and renders them more susceptable of any impression. If the heat be long continued, it produces a moisture upon the skin, called perspiration, which, by relaxing the cuticle, keeps the subjacent nervous papilla in a supple state, and obvious to every impulse. It likewise exposes the extremities of the nerves to external impressions, by keeping the skin in a smooth state, and void of corrugation. Heat also, by increasing the secretion of perspiration, causes the perspirable matter (similar to what occurs in other increased glandular discharge, as the saliva, the mucus of the nose, &c.) to be very much attenuated, and conseqently fit for being easily and quickly evaporated, without the same portion of it remaining long upon the skin, or leaving much residuum; which renders the cuticle very thin and fine, and of consequence fit for transmitting sensations through its substance. By increasing the perspiration, heat diminishes the other evacuations, and even the secretions. The urine is separated but in small quantity, and the alvine evacuation is very slow. The bile however must be excepted, which is considerably increased in quantity, and as some think rendered more acrimonious in quality. The disposition of the body and juices to putrefaction is also much augmented. ibid. Chap. II. p. 4. [[margin]] Effects of cold on the living human body. [[/margin]] Cold, on the contrary, in similar circumstances, corrugates or wrinkles the cuticle, and causes the cutaneous papilla to contract, and to retire deeper into the skin. It also [[strikethrough]] in [[/strikethrough]] closes the orifices of the cutaneous glands, and thus prevents the access of any irritating substance. By contracting the nervous papilla, it diminishes perspiration, and probably makes the perspirable matter more viscid, which renders the cuticle more dry and rigid, and even considerably thicker; by all which the accuracy of sensation or feeling is much diminished. (*) Perhaps too, as Mr. Montesquieu [[line drawn to indicate bottom margin]] (*) Mr. Winslow remarks, that the insensible perspiration is always greatest where the feeling is required to be most accurate, as in the palms of the hands, insides of the fingers, &c. - [[underline]] Winslow's Anatomy [[/underline]]. ob