In order, however, to see if I could, by exposure, cause the well-known symptoms of cold, I have made many experiments, some of which I will name: I have walked in snow and slop with low shoes until both shoes and socks were soaked through, and have sat thus for an hour or more; after wearing all-wool flannels during moderate weather, I have, upon the approach of _colder weather_, removed my under-garments, and have then attended to my outdoor affairs, minus the overcoat habitually worn; I have slept in winter in a current blowing directly about my head and shoulders; upon going to bed, I have sat in a strong current, _entirely nude_, for a quarter of an hour, on a very cold, damp night in the fall of the year; I have worn a flannel gown, and slept under heavy-weight bed-covers one night, and in cotton night-shirt and light-weight bed-clothes the next. These and similar experiments I have made repeatedly, and have never been able to catch cold. I become cold, sometimes quite cold, and become warm again, that is all. On the other hand, changing the form of my experiments, returning to my old way, the prevalent style of living——a “generous diet” and a full meal every five or six hours through the day——I have found no difficulty in _accumulating_ a cold; and within a reasonable length of time could count upon it, although, now, a part of the programme consisted in taking the most extreme care to avoid what are commonly reckoned as exposures——keeping my feet ever warm and dry, paying strict attention to wraps,[11] etc. This is not simply my own individual experience, but, also, of others who, either of their own accord or through my suggestion, have carefully studied the matter; while rational hygienists, generally, attest to the main fact, that they endure all the ordinary vicissitudes of life without often being troubled with this most disagreeable complaint. [Footnote 11: Said an observing friend to me: “I am apt to catch cold when I _put on_ my winter flannels; why is that?” With those who may happen to be already near the brink, this effect is likely to follow the addition of an extra layer of flannel to the ordinary dress, unless they leave out a layer of food, so to say, or the weather happens to be enough colder on that day, to counteract the extra clothing.]