[51] This experiment and several others in this book, are taken from Professor Bowditch’s little book called _Hints for Teachers of Physiology_, a work which should be mastered by every teacher of physiology in higher schools. [52] The teacher or student who is disposed to study the subject more thoroughly and in more detail than is possible in a class text-book, will find all that is needed in the following excellent books, which are readily obtained by purchase, or may be found in the public libraries of larger towns: Dulles’ _Accidents and Emergencies;_ Pilcher’s _First Aid in Illness and Injury_; Doty’s _Prompt Aid to the Injured;_ and Johnston’s “Surgical Injuries and Surgical Diseases,” a special article in Roosevelt’s _In Sickness and in Health_. [53] “A tourniquet is a bandage, handkerchief, or strap of webbing, into the middle of which a stone, a potato, a small block of wood, or any hard, smooth body is tied. The band is tied loosely about the limb, the hard body is held over the artery to be constricted, and a stick is inserted beneath the band on the opposite side of the limb and used to twist the band in such a way that the limb is tightly constricted thereby, and the hard body thus made to compress the artery (Fig. 160). “The entire circumference of the limb may be constricted by any sort of elastic band or rubber tube, or any other strong elastic material passed around the limb several times on a stretch, drawn tight and tied in a knot. In this way, bleeding may be stopped at once from the largest arteries. The longer and softer the tube the better. It requires no skill and but little knowledge of anatomy to apply it efficiently.” Alexander B. Johnson, Surgeon to Roosevelt Hospital, New York City. [54] Corrosive sublimate is probably the most powerful disinfectant known. A solution of one part in 2000 will destroy microscopic organisms. Two teaspoonfuls of this substance will make a solution strong enough to kill all disease germs. [55] The burning of sulphur produces sulphurous acid, which is an irrespirable gas. The person who lights the sulphur must, therefore, immediately leave the room, and after the lapse of the proper time, must hold his breath as he enters the room to open the windows and let out the gas. After fumigation, plastered walls should be white-washed, the woodwork well scrubbed with carbolic soap, and painted portions repainted. [56] Put copperas in a pail of water, in such quantity that some may constantly remain undissolved at the bottom. This makes a saturated solution. To every privy or water-closet, allow one pint of the solution for every four persons when cholera is about. To keep privies from being offensive, pour one pint into each seat, night and morning.