Certain chemical agents that are capable of destroying micro-organisms and their spores have come, of late years, into general use. A form of mercury, called _corrosive sublimate_, is a most efficacious and powerful germicide, but is exceedingly poisonous and can be bought only under restrictions.[54] _Carbolic acid, chloride of lime, permanganate of potash_, and various other preparations made from zinc, iron, and petroleum, are the chemical disinfectants most commonly and successfully used at the present time. There are also numerous varieties of commercial disinfectants now in popular use, such as Platt's chlorides, bromo-chloral, sanitas, etc., which have proved efficient germicides.

Instructions for the Management of Contagious Diseases.

The following instructions for the management of contagious diseases were prepared for the National Board of Health by an able corps of scientists and experienced physicians.

403. Instructions for Disinfection. Disinfection is the destruction of the poisons of infectious and contagious diseases. Deodorizers, or substances which destroy smells, are not necessarily disinfectants, and disinfectants do not necessarily have an odor. Disinfection cannot compensate for want of cleanliness nor of ventilation.

404. Disinfectants to be Employed. 1. Roll sulphur (brimstone); for fumigation.

2. Sulphate of iron (copperas) dissolved in water in the proportion of one and a half pounds to the gallon; for soil, sewers, etc.

[NOTE. A most useful little manual to consult in connection with this chapter is the _Hand-Book of Sanitary Information_, written by Roger S. Tracy, Sanitary Inspector of the New York City Health Department.

Price, 50 cents.]

3. Sulphate of zinc and common salt, dissolved together in water in the proportion of four ounces sulphate and two ounces salt to the gallon; for clothing, bed-linen, etc.

405. How to Use Disinfectants. 1. _In the sick-room._ The most available agents are fresh air and cleanliness. The clothing, towels, bed-linen, etc., should, on removal from the patient, and before they are taken from the room, be placed in a pail or tub of the zinc solution, boiling-hot, if possible.

All discharges should either be received in vessels containing copperas solution, or, when this is impracticable, should be immediately covered with copperas solution. All vessels used about the patient should be cleansed with the same solution.

Unnecessary furniture, especially that which is stuffed, carpets, and hangings, should, when possible, be removed from the room at the outset; otherwise they should remain for subsequent fumigation and treatment.

2. _Fumigation_. Fumigation with sulphur is the only practicable method for disinfecting the house. For this purpose, the rooms to be disinfected must be vacated. Heavy clothing, blankets, bedding, and other articles which cannot be treated with zinc solution, should be opened and exposed during fumigation, as directed below. Close the rooms as tightly as possible, place the sulphur in iron pans supported upon bricks placed in washtubs containing a little water, set it on fire by hot coals or with the aid of a spoonful of alcohol, and allow the room to remain closed for twenty-four hours. For a room about ten feet square, at least two pounds of sulphur should be used; for larger rooms, proportionally increased quant.i.ties.[55]

3. _Premises_. Cellars, yards, stables, gutters, privies, cesspools, water-closets, drains, sewers, etc., should be frequently and liberally treated with copperas solution. The copperas solution is easily prepared by hanging a basket containing about sixty pounds of copperas in a barrel of water.[56]

4. _Body and bed clothing, etc_. It is best to burn all articles which have been in contact with persons sick with contagious or infectious diseases. Articles too valuable to be destroyed should be treated as follows:

_(a)_ Cotton, linen, flannels, blankets, etc., should be treated with the boiling-hot zinc solution; introduce piece by piece, secure thorough wetting, and boil for at least half an hour.

_(b)_ Heavy woolen clothing, silks, furs, stuffed bed-covers, beds, and other articles which cannot be treated with the zinc solution, should be hung in the room during fumigation, their surfaces thoroughly exposed and pockets turned inside out. Afterward they should be hung in the open air, beaten, and shaken. Pillows, beds, stuffed mattresses, upholstered furniture, etc., should be cut open, the contents spread out and thoroughly fumigated. Carpets are best fumigated on the floor, but should afterward be removed to the open air and thoroughly beaten.

Books for Collateral Study. Among the many works which may be consulted with profit, the following are recommended as among those most useful: Parkes _Elements of Health_; Canfield's _Hygiene of the Sick-Room;_ Coplin & Bevan's _Practical Hygiene;_ Lincoln's _School Hygiene_; Edward Smith's _Health_; McSherrys _Health; American Health Primers_ (12 little volumes, edited by Dr. Keen of Philadelphia); Reynold's _Primer of Health_; Corfield's _Health_; Appleton's _Health Primers;_ Clara S. Weeks' _Nursing_; Church's _Food_; Yeo's _Food in Health and Disease;_ Hampton's _Nursing, its Principles and Practice_; Price's _Nurses and Nursing;_ Cullinworth's _Manual of Nursing_; Wise's _Text-Book of Nursing_ (2 vols.); and Humphrey's _Manual of Nursing_.

Chapter XV.

Experimental Work in Physiology.

406. The Limitations of Experimental Work in Physiology in Schools.

Unlike other branches of science taught in the schools from the experimental point of view, the study of physiology has its limitations.

The scope and range of such experiments is necessarily extremely limited compared with what may be done with the costly and elaborate apparatus of the medical laboratory. Again, the foundation of physiology rests upon systematic and painstaking dissection of the dead human body and the lower animals, which mode of study very properly is not permitted in ordinary school work. Experiments upon the living human body and the lower animals, now so generally depended upon in our medical and more advanced scientific schools, for obvious reasons can be performed only in a crude and quite superficial manner in secondary schools.

Hence in the study of physiology in schools many things must be taken for granted. The observation and experience of medical men, and the experiments of the physiologist in his laboratory must be depended upon for data which cannot be well obtained at first hand by young students.

407. Value of Experiments in Physiology in Secondary Schools. While circ.u.mstances and regard for certain proprieties of social life forbid the use of a range of experiments, in anatomy and physiology, such as are permitted in other branches of science in secondary schools, it by no means follows that we are shut out altogether from this most important and interesting part of the study. However simple and crude the apparatus, the skillful and enthusiastic teacher has at his command a wide series of materials which can be profitably utilized for experimental instruction.

As every experienced teacher knows, pupils gain a far better knowledge, and keep up a livelier interest in any branch of science, if they see with their own eyes and do with their own hands that which serves to illuminate and ill.u.s.trate the subject-matter.

[NOTE. For additional suggestions and practical helps on the subject of experimental work in physiology the reader is referred to Blaisdell's _How to Teach Physiology_, a handbook for teachers. A copy of this pamphlet will be sent postpaid to any address by the publishers of this book on receipt of ten cents.]

The experimental method of instruction rivets the attention and arouses and keeps alive the interest of the young student; in fact, it is the only true method of cultivating a scientific habit of study[57]. The subject-matter as set forth on the printed pages of this book should be mastered, of course, but at the same time the topics discussed should be illuminated and made more interesting and practical by a well-arranged series of experiments, a goodly show of specimens, and a certain amount of microscopical work.

408. The Question of Apparatus. The author well understands from personal experience the many practical difficulties in the way of providing a suitable amount of apparatus for cla.s.sroom use. If there are ample funds for this purpose, there need be no excuse or delay in providing all that is necessary from dealers in apparatus in the larger towns, from the drug store, markets, and elsewhere. In schools where both the funds and the time for such purposes are limited, the zeal and ingenuity of teachers and students are often put to a severe test.

Fortunately a very little money and a great deal of ingenuity and patience will do apparent wonders towards providing a working supply of apparatus.

It will be noticed that many of the experiments in the preceding chapters of this book can be performed with very simple, and often a crude and home-made sort of apparatus. This plan has been rigidly followed by the author, first, because he fully realizes the limitations and restrictions of the subject; and secondly, because he wishes to emphasize the fact that expensive and complicated apparatus is by no means necessary to ill.u.s.trate the great principles of anatomy and physiology.

409. Use of the Microscope. To do thorough and satisfactory work in physiology in our higher schools a compound microscope is almost indispensable. Inasmuch as many of our best secondary schools are equipped with one or more microscopes for use in other studies, notably botany, it is much less difficult than it was a few years ago to obtain this important help for the cla.s.ses in physiology.

[Ill.u.s.tration: Fig. 170.--A Compound Microscope]

For elementary cla.s.s work a moderate-priced, but well-made and strong, instrument should be provided. If the school does not own a microscope, the loan of an instrument should be obtained for at least a few weeks from some person in the neighborhood.

The appearance of the various structures and tissues of the human body as revealed by the microscope possesses a curious fascination for every observer, especially for young people. No one ever forgets the first look at a drop of blood, or the circulation of blood in a frog's foot as shown by the microscope.

[NOTE. For detailed suggestions in regard to the manipulation and use of the microscope the student is referred to any of the standard works on the subject. The catalogues of scientific-instrument makers of our larger cities generally furnish a list of the requisite materials or handbooks which describe the use of the various microscopes of standard make.

The author is indebted to Bergen's _Elements of Botany_ for the following information concerning the different firms which deal in microscopes. "Several of the German makers furnish excellent instruments for use in such a course as that here outlined. The author is most familar with the Leitz microscopes, which are furnished by Wm.

Krafft, 411 West 59th St., New York city, or by the Franklin Educational Co., 15 and 17 Harcourt St., Boston. The Leitz Stand, No.

IV., can be furnished duty free (for schools only), with objectives 1, 3, and 5, eye-pieces I. and III., for $24.50. If several instruments are being provided, it would be well to have part of them equipped with objectives 3 and 7, and eye-pieces I. and III.

"The American manufacturers, Bausch & Lomb Optical Company, Rochester, N.Y., and No. 130 Fulton St., New York city, have this year produced a microscope of the Continental type which is especially designed to meet the requirements of the secondary schools for an instrument with rack and pinion coa.r.s.e adjustment and serviceable fine adjustment, at a low price. They furnish this new stand, 'AAB,' to schools and teachers at 'duty-free' rates, the prices being for the stand with two eye-pieces (any desired power), ?-inch and -inch objectives, $25.60, or with 2-inch, ?-inch, and -inch objectives, and two eye-pieces, $29.20. Stand 'A,' the same stand as the 'AAB,' without joint and with sliding tube coa.r.s.e adjustment (as in the Leitz Stand IV.), and with three eye-pieces and ?-inch and -inch objectives, is furnished for $20.40. Stand 'A,' with two eye-pieces, ?-inch and ?-inch objectives, $20.40."]

410. The Use of the Skeleton and Manikin. The study of the bones by the help of a skeleton is almost a necessity. To this intent, schools of a higher grade should be provided both with a skeleton and a manikin. If the former is not owned by the school, oftentimes a loan of one can be secured of some medical man in the vicinity. Separate bones will also prove useful. In fact, there is no other way to study properly the structure and use of the bones and joints than by the bones themselves. A good manikin is also equally serviceable, although not so commonly provided for schools on account of its cost.

411. The Question of Vivisection and Dissection. There should be no question at all concerning vivisection. _In no shape or form should it be allowed in any grade of our schools._ Nor is there any need of much dissection in the grammar-school grades. A few simple dissections to be performed with fresh beef-joints, tendons of turkey legs, and so on, will never engender cruel or brutal feelings toward living things. In the lower grades a discreet teacher will rarely advise his pupils to dissect a dead cat, dog, frog, or any other animal. Instead of actual dissection, the pupils should examine specimens or certain parts previously dissected by the teacher,--as the muscles and tendons of a sheep, the heart of an ox, the eye of a codfish, and so on. Even under these restrictions the teacher should not use the knife or scissors before the cla.s.s to open up any part of the specimen. In brief, avoid everything that can possibly arouse any cruel or brutal feeling on the part of young students.

In the higher schools, in normal and other training schools, different conditions prevail. Never allow vivisection in any form whatever, either in school or at home. Under the most exact restrictions students in these schools may be taught to make a few simple dissections.

Most teachers will find, however, even in schools of a higher grade, that the whole subject is fraught with many difficulties. It will not require much oftentimes to provoke in a community a deal of unjust criticism. A teacher's good sense and discretion are often put to a severe test.

Additional Experiments.

To the somewhat extended list of experiments as described in the preceding chapters a few more are herewith presented which may be used as opportunity allows to supplement those already given.