By L. D. Rodgers, A. M., M. D.

(From Peoples' Health Journal, October, 1885.)

Considerable scientific attention has recently been very profitably devoted to the question of fabrics for underwear most conducive to health. Interesting experiments have been made developing facts which will surprise almost everyone on learning them for the first time. One of the simplest and most readily understood of these experiments was that of filling tin cans with hot water and wrapping each one with a different fabric, and then observing with thermometers the varying rapidity in the loss of heat. Thus showing accurately the relative heat preserving value of each fabric. Of two cans surrounded with the same amount of common cotton batting, in one case the cotton being compressed, and the other not, the loss of heat was found to be much more rapid in the former than in the latter. Showing, therefore, conclusively, that loose open fabrics are warmer than those which contain less air in their interstices. This accords with the well-known fact that the new flannel is warmer than old which has undergone the felting or fulling processes. Assuming that flannel contains 100 units of air in its interstices, the permeability of other substances have been found to be as follows: Linen, 58; silk, 40; buckskin, 58; kid, 1; chamois, 51. Doubling the layers of any given material does not diminish the loss of heat in the same proportion. Assuming the loss of heat through a single layer to be 100, through a double layer of the same material it is found to be as follows: Thin silk, 97; gutta percha, 96; shirtings, 95; stout silk, 94; thick home-spun linen, 91; chamois leather, 88-90; flannel, 86; summer buckskin, 88; winter buckskin, 86. Thus we see that the loss of heat through two layers of thin silk is only three per cent. less than through one layer. The inference is that what the substance is and what its weight, does not make so much difference as its texture and volume. How the body may lose heat rapidly by wet clothing, and ill results follow, is shown by the following experiment: A rabbit was shorn of its fur, its temperature was then found to be 102 degrees. It was wrapped with a wet cloth and placed in a room, the temperature of which was 66 degrees. At the expiration of five hours the temperature of the rabbit was found to be 76 degrees. The capacity of water to absorb heat is known to be greater than any other substance. Now, when our clothing is damp from perspiration or from any other cause, our bodies lose just as much heat as the moisture in our clothing is capable of absorbing. The importance of always having dry material next to the skin is evident, and that material which will retain the least moisture is the best. Woolen fibre is found to answer this purpose more nearly than any other. In addition to its well-known filtering capacity, it has a greater stimulating action upon the skin than any other. On the other hand, cotton fibre, on account of its great capillary attraction, rapidly absorbs and retains moisture. A fabric, therefore, so constructed as to allow a layer of woolen fibre to lie between the skin and a layer of cotton fibre, and sufficiently open and loose as to contain the largest possible amount of air is the ideal. The Jaros Hygienic Underwear material, a new fabric, seems beautifully adapted to this end. A layer of woolen fibres, soft and fleecy, is firmly held on one side of and in the meshes of an exceeding porous cotton fabric, so that while one extremity of a fibre lies against the skin, the other is in contact with the cotton; thus admitting of the rapid transference of all dampness of perspiration to the cotton where it is retained, and consequently leaving no moisture next to the skin to absorb and diminish the heat of the body. The importance of this subject, and the possibilities of this new fabric for the prevention of colds, and their resultant diseases, can only be appreciated when we remember the simple fact that it is impossible to take a cold so long as a healthy condition of the skin, and an even temperature of the surface of the body, are maintained.