Much has been written on the advantages of woolen underwear, on the ground that since clothing is intended to retain the body heat and since wool acts as a more effective non-conductor of heat than either cotton or linen, therefore the woolen undergarment is of the greatest value. Another argument urged in favor of woolen undergarments is that they check the chill resulting from excessive perspiration, since the non-conducting power of wool prevents any rapid evaporation of perspiration responsible for the lower temperatures. For this reason, woolen undergarments are always recommended for those climbing mountains or in occupations where violent exercise is likely to be followed by rest or quiet in cold air. The objection to woolen undergarments at all times is that with sensitive skins irritation may take place, and the odd saying of Josh Billings becomes pertinent, namely, that "the only thing that a wool shirt is good for is to make a man scratch and forget his other troubles." Underwear woolen only in part may take the place of all-wool garments and have the further advantage of being less expensive. The amount of clothing worn in winter depends, or should depend, on the character of the occupation of the wearer. Formerly, heavy woolen underclothes were almost universally worn throughout the winter without regard to the employment of the individual. When an out-of-door occupation was pursued a large part of the time or when the temperature indoors was hardly above freezing, then heavy clothing was essential; but now that much time is spent in a well-heated house or office, heavy clothing is as objectionable as overheated rooms, and the comfort and health of the body will be much better preserved by not increasing the weight of clothing except when exposed to the outer air. It must be remembered, however, that old persons, whose circulation is impaired and who are forced to lead sedentary lives, will always have difficulty in maintaining the body heat unless the outer temperature is high, and for such, woolen undergarments are very useful. The outer garments in winter, to be efficient, must have two qualities, namely, an impervious surface so that winds may not penetrate and a loose open weave in which air may be held so that warmth may be secured. Rubber boots, although very common in the country, are not desirable as a foot covering, because they do not allow the perspiration to evaporate, but rather hold the foot in a moist condition very detrimental to it. Rubber-cloth overshoes or arctics are much better than rubber boots, and felt overshoes are equally satisfactory. Chilblains are fostered by the use of rubber boots, and cloth shoes are a great relief when the feet are thus affected. _Ventilation of bedroom._