An infectious disease is one which is capable of infecting other
persons, causing the same disease in them ; smallpox and malarial
fever are both infectious. A contagious disease is that form of in-
fectious disease which is spread to others by contact with the person
infected. Smallpox is a contagious disease. Malarial fever is
not a contagious disease because no amount of simple contact with
an infected person can produce the disease, the infection of which
must be carried by a mosquifo. Disinfection is the process of de-
stroying the infectious germ or agent to prevent the spread of the
An infectious disease may be due to an animal or a vegetable
organism ; in either case the parasite is so small as to be visible only
under the microscope or not visible at all.
Some of the diseases due to animal parasites are malaria, sleeping
sickness, amoebic dysentery, and probably yellow fever and dengue.
Sepsis or putrefaction is a particular form of infection; anti-
septics are those substances which prevent putrefaction either by
destroying the germs or preventing their growth.
Sterilisation is the process of killing disease germs; it has the
same meaning as disinfection, but is usually limited to disinfection
In all disinfection work it should be constantly borne in mind that
the agent employed must be used at the proper strength, for a definite
length of time, and must be brought thoroughly in contact with all
parts of the substance to be disinfected.
The disinfectants commonly used by the medical department in
addition to direct sunlight, are dry heat, boiling water, steam, cor-
INFECTION AND DISINFECTION 201
rosive sublimate, phenol, cresol, iodine, quicklime, chlorinated lime,
formaldehyde solution, and sulphur.
Dry heat is seldom used, as the high temperature necessary in-
jures fabrics, and the heat has little penetrating power.
Flowing steam is used especially in the operating room for dis-
Boiling is a simple and effective method of disinfection for metallic
or earthen utensils, and for cotton or linen fabrics. Woolen and
leather substances are injured by steam or boiling water. The ad-
dition of one per cent of carbonate of soda increases the disinfecting
power of the boiling water and prevents instruments from rusting.
Actual boiling for ten minutes is ordinarily sufficient.
Corrosive sublimate in acid solution (0.2 per cent hydrocloric
acid) is one of the most effective chemical disinfectants; for this
purpose solutions of corrosive sublimate i : 1000 are usually em-
ployed. Its disadvantages are that it is decomposed by albuminous
matters, and by hard waters, and that it corrodes and rapidly de-
stroys metals. Solutions should be freshly prepared, and in soft
water, such as rain water or distilled water. When only hard water
is available some other disinfectant should be used.
Phenol is a valuable disinfectant in five per cent solution. It,
like corrosive sublimate, coagulates albumin and thereby to some
extent protects the inclosed germs from its disinfectant action.
Cresol in one per cent solution has about the same value as phenol
at five per cent. Albuminous fluids do not interfere with its action.
Iodine in 3-5 per cent alcoholic solution is very valuable for dis-
infecting wounds, or sterilizing the skin before operation.
Quicklime is a somewhat uncertain disinfectant because of the
fact that it is rapidly decomposed on exposure to the air and moist-
ure. Milk of lime, a ten per cent solution of quicklime, is ordi-
narily employed. To be effective the lime must have been freshly
burned and be unslaked.
Chlorinated lime is used ordinarily in four per cent solution in
water. Its activity depends on the amount of chlorine it contains,
and, as it is rapidly changed on exposure to the air, it should have
been freshly opened and prepared in order to be effective.
Formalin is a solution of formaldehyde gas in water, its disinfect-
ing powers depending on the dissolved gas. It is sometimes used in
the form of a spray, but ordinarily the gas itself is employed.
The only apparatus required is a large open vessel, protected by
some non-conductive material to prevent the loss of heat from
within. An ordinary milk pail, set into a pulp or wooden bucket,
will answer every purpose, although a special container (Fig. 125)
will be found of considerable advantage. This container or genera-
tor consists of a simply constructed tin can with broad flaring top.
Its full height is 1^/2 inches, the height from the bottom to the
flaring top being about 8 inches. The lower or round section is 10
inches in diameter, while the flaring top is 17^2 inches in diameter
FIG. 125. Container for Generating Formaldehyde Gas. (Formaldehyde-potassium,
at its top. The container is made of good quality of bright tin, is
supplied with a double bottom with *4 i ncn a i r space between the
two layers, and is entirely covered on sides and bottom with asbestos
paper. The asbestos paper and double bottom serve effectively to
retain the heat which is generated by the vigorous chemical reaction
occurring within, and which is essential to the complete production
and liberation of the gas. This special container can be made by
any tinner of ordinary intelligence, and costs but a few dollars.
The following preparatory steps should be taken
(a) Have all windows and doors (except door of egress) tightly
closed. Securely paste strips of paper over keyholes, over cracks,
INFECTION AND DISINFECTION 203
above, beneath and at sides of windows and doors, over stove holes
and all openings in walls, ceiling and floor. If opening be large,
paste several thicknesses of paper over opening. Carefully stop up
the fireplace if there be one. There must be no opening through
which gas can escape.
(b) All articles in the room that can not be washed must be
spread out on chairs or racks. Clothing, bed covers, etc., should
be hung on lines stretched across the room. Mattresses should be
opened and set on edge. Window shades and curtains spread out
at full length. If there is a trunk or chest in the room, open it but
let nothing stay in it. Open the pillows so that the gas can reach
the feathers. Do not pile articles together.
With the room thus prepared, as is essential in any form of
gaseous disinfection, crystals of potassium permanganate (16 ounces
to each 1,000 cubic feet of room space) are placed in the container.
Over this is poured " formalin," or the 37^2 per cent aqueous solu-
tion of formaldehyde (16 ounces to every 1,000 cubic feet of room
space), the temperature of the room must not be below 60 F. The 1
formaldehyde gas is promptly liberated by the vigorous reaction of
the formalin and potassium permanganate, and arises from the
generator in immense volume in the form of an inverted cone. It is
consequently necessary that all preparations be made in advance,
and that the operator leave the room at once on the combination of
the two chemicals.
The door or window of exit will be promply closed and sealed
and the room left closed for at least four hours.
As in all methods of disinfecction, success largely depends upon
the care which is exercised and the attention which is given to every
detail. Simple as the method is, neglect of any of the following
points may result in complete failure :
1. The room should be sealed and prepared as described.
2. The potassium permanganate (16 ounces to every 1,000 cubic
feet of room space) should be placed in the apparatus or generator.
The permanganate must be put in before the formaldehyde solution.
3. The 37^ per cent formaldehyde solution (16 ounces to the
1,000 cubic feet of room space) should then be poured over the
4. As the gas is given off in immense volume immediately after
the mixture of the formaldehyde and permanganate, the operator
must leave the room at once. All preparations must have been
finished in advance.
5. The door or window of exit must be promptly closed and
sealed, so that there will be no escape of gas, and the room should be
left closed for four hours.
Whenever practicable, the special generator, previously described,
should be used. In the absence of such a container, however, a
milk pail may be used. The milk pail should be set, so as to fit
snugly into a wooden or pulp bucket, or it may be wrapped tightly
with several layers of asbestos paper. This is done to retain the
heat within the generator and is very important to the proper genera-
tion of the gas.
Care must be taken not to place too much formaldehyde in a
single container. The reaction is violent and there is great effer-
vescence and bubbling. If the room is too large to be disinfected
with one generator, use as many more as are required, and place in
each only a reasonable amount.
The following quantities may be used safetly in the containers
10 or 12 quart milk pail, Formaldehyde, 16 ounces;
Permanganate, 16 ounces.
14 quart milk pail, Formaldehyde, 24 ounces;
Permanganate, 24 ounces.
Special apparatus described above,
Formaldehyde, 32 ounces;
Permanganate, 32 ounces.
Sulphur fumes are valuable as a disinfectant chiefly because of
their power of destroying animal carriers of infection such as mos-
quitoes, fleas, lice, and rats ; they also have some value as destroyers
of bacteria but they injure metals, fabrics, food-stuffs and colors.
Four pounds of rolled sulphur are required per 1,000 cubic feet
of air space. The room must be tightly closed and all cracks and
openings sealed; the sulphur broken in small pieces is placed in a
pan and a small quantity of alcohol poured over it ; the pan is then
placed on bricks in a tub of water, the tub placed on a table, not on
the floor, and the alcohol ignited. The water serves two purposes :
it increases the efficiency of the sulphur dioxid by virtue of the
vapor liberated by the heat of the burning sulphur, and it also lessens
the danger of fire (Fig. 126).
INFECTION AND DISINFECTION 205
Sulphur candies can be used instead of crude sulphur, but care
must be taken to use sufficient candles. The average candle on the
market contains one pound of sulphur. Three of these will be re-
quired in the disinfection of a small room, 10x10x10. Do not use
a less number, no matter what directions may accompany the candle.
The water- jacketed candle is preferable. Partly fill tin around
candle with water and place candles in a pan on the table, not on
the floor. Let one-half pint of water be vaporized with each candle.
In the absence of moisture, the fumes of sulphur have no disin-
fecting power. Keep the room closed for 10 hours at least.
The prevention of the spread of infectious diseases requires abso-
lute cleanliness, free ventilation, disinfection, and isolation, and in the
FIG. 126. Burning Sulphur.
case of diseases such as malaria, yellow fever, dengue, typhus fever,
plague, etc., which are carried by insects, protection from the insect
carriers. In the bacterial diseases the infectious agent is usually
contained in one or more of the excretions of the patient, depending
upon the particular disease. As the bacteria can not get into the
air from moist excretions these should not be allowed to drv but
should be disinfected and removed at once.
The dust of the ward becomes infected from excretory particles
which have accidentally become dried; hence every care should be
taken to avoid raising dust.
Flies and other insects may carry the infection on their feet or
other parts of their bodies, therefore the discharges should be care-
fully protected from insects.
Sputum should be received in covered cups containing a one per
cent solution of cresol, or five per cent formalin. Sometimes paper
cups are used, the cups and contents being burned together.
Feces are best disinfected with milk of lime, ten per cent, or som-
tion of chlorinated lime, four per cent.
Urine should be sterilized by adding sufficient carbolic acid to
make a five per cent solution, or enough corrosive sublimate to make
a solution of i :iooo.
In all cases the disinfectant solution employed should be equal in
bulk to the material to be disinfected and should be thoroughly mixed
with the excretion and allowed to stand at least an hour.
The vessels which have been used as containers should be boiled.
Infected clothing and bedding should be disinfected by steam, or
formaldehyde gas in a tight chamber, but steam should not be used
for woolens. If the infection is gross, as when the bed linen of a
typhoid or cholera patient is soiled with feces, the articles should
be soaked in a cold phenol or cresol solution containing two per
cent of soft soap for several hours.
Boiling is applicable to linen or cotton fabrics.
Mattresses of which the hair is infected require steam under press-
ure, the ticking having been opened up.
Metal beds should be washed with five per cent solution of carbolic
Disinfection of rooms: The contents of the room should not be
removed. Articles of bedding and clothing should be hung on
lines or the backs of chairs so as to expose as much surface as
possible. The room must then be made practically airtight by sealing
windows, doors, ventilating openings, and all other cracks and open-
ings with strips of paper and ordinary flour paste. Formaldehyde
gas or sulphuric-acid gas is then introduced in proper proportion
and the room kept sealed for twenty-four hours.
The latest investigations indicate that this preliminary fumiga-
tion is of little value and may be omitted ; the mechanical cleansing
is the important feature.
The treatment of the walls and ceiling will depend upon their
nature; if hard-finished or painted they should be scrubbed with hot
water and soap, and then with an acid solution of corrosive subli-
mate, i :iooo, and repainted; a preliminary scrubbing of the walls
with slices of stale bread is very effective for mechanical cleansing;
bread so used should be burned. If the walls are calcimined or
whitewashed they should be washed with soap and hot water, fol-
lowed by ten per cent solution of chlorinated lime or five per cent of
phenol, and recalcimined ; sublimate should not be used because it is
decomposed by the lime. If the walls are papered the paper should
INFECTION AND DISINFECTION 207
be removed, after which the treatment is the same as for calcimined
walls. Especial attention should be given to the lower parts of the
walls, the first six feet from the floor.
All woodwork is to be scrubbed with soap and hot water, followed
by corrosive sublimate ; painted or varnished woodwork should be
repainted or varnished. Floors with hard finish should have the
old finish removed with turpentine and a new coat applied.
After the completion of the disinfection the room with all doors
and windows open should be freely exposed to the action of sun
and air for several days.
Disinfection of tent age: Everything should be removed from the
tent for disinfection by the methods appropriate to each. The in-
terior of the canvas, the poles, and the wooden floors, if any, should
then be sprayed or washed with a two per cent solution of cresol
or five per cent phenol. The tent is then removed to a new site,
pitched inside out and exposed to the sun and air for twenty-four
hours. The ground under the old tent floor should be policed and
scraped, and sprinkled with a ten per cent solution of chlorinated
lime or freshly slaked quicklime.
INSTRUMENTS AND APPLIANCES
THE following is a brief description of those instruments and
appliances which require explanation :
Explanation of Figs. 127 to 135.
Atomiser, hand: An instrument for producing a fine spray
Bistoury: A long, narrow knife, which is either straight or curved,
sharp or blunt pointed (Fig. 128).
Bougie: An instrument used for
dilating strictures (Fig. 129).
Bougie a boule: An instrument
used to locate strictures (Fig. 130).
Bougie, filiform: .A hairlike
bougie for passing through tight
strictures (Fig. 131).
Catheter: A tube for passing
through the urethra into the
bladder to draw off the urine.
Catheters are made of silver, glass
webbing, or rubber, of various
sizes, and sometimes contain a wire called a stylet (Fig. 132).
Catlin: A double-edged amputating knife (Fig. 133).
Caustic-holder: A little case for holding caustic, usually made of
gutta-percha or silver (Fig. 134).
Curette: An instrument used for scraping bones and unhealthy
wounds (Fig. 135).
INSTRUMENTS AND APPLIANCES 209
FIG. 129. FIG. 130. FIG. 131.
Explanation of Figs. 136 to 139.
Cutting shears: A strong scissors for cutting plaster bandages
Clamp, pile: Ivory faced blades, to prevent burning of tissues
while using thermocantery (Fig. 137).
Clamp, toivel: Employed to secure the towel of gauze protector
to the edges of the wound (Fig. 138).
Cooler, prostatic: For cooling and massaging the prostate gland
INSTRUMENTS AND APPLIANCES 211
Explanation of Figs. 140 to 145.
Divulsor, urethral: For rapid dilatation and divulsion of strictures
Director: An instrument with a groove in which to guide the
point of a knife (Fig. 141).
Drill, bone: An instrument for boring holes in bone (Fig. 142).
Eudoscope, urethral: For examination of the urethra (Fig. 143).
Forceps, bullet: An instrument with separate blades used for
extracting bullets (Fig. 144).
Forceps, dental: An instrument used for extracting teeth (Fig.
INSTRUMENTS AND APPLIANCES 213
Explanation of Figs. 146 to 151.
Forceps, dissecting: Plain forceps used for dissecting purposes
Forceps, dressing: Forceps with scissor handles, used for remov-
ing old dressings from wounds and sores (Fig. 147).
Forceps, bone holding: For'holding bone during operations (Fig.
Forceps: Ear dressing (Fig. 149).
Forceps: Nasal dressing (Fig. 150).
Forceps, steriliser: For removing instruments from sterilizer
INSTRUMENTS AND APPLIANCES 215
Explanation of Figs. 152 to 157.
Forceps, tongue: For grasping and holding the tongue during
anaesthesia (Fig. 152).
Forceps, gouge: A strong forceps, cutting at the points, so as to
gouge bone (Fig. 153).
Forceps, hemostatic: Forceps for taking up articles (Fig. 154).
Forceps, List on' s bone: A strong bone forceps for cutting bone
in operations (Fig. 155).
Forceps, mouse-tooth: Forceps with fine, sharp teeth, used in
dissecting (Fig. 156).
Forceps, needle-holder: A forceps to hold the needle in sewing
wounds (Fig. 157).
INSTRUMENTS AND APPLIANCES 217
Explanation of Figs. 158 to 164.
Forceps, sequestrum: A strong forceps for pulling away dead
bone (Fig. 158).
Gag, mouth: An appliance for holding the mouth open (Fig. 159).
Gouge and chisel: For gouging and splitting bone (Fig. 160).
Head mirror: A round mirror worn on the forehead in the ex-
amination of the throat and ear (Fig. 161).
Inflator, Politzer: A rubber air bag with nozzle used in inflating
the ear (Fig. 162).
Inhaler, chloroform: A framework covered with gauze or flannel
for administering chloroform (Fig. 163).
Inhaler, ether, Allis: An appliance for the administration of ether
INSTRUMENTS AND APPLIANCES
Explanation of Figs. 165 to 175.
Knife, amputating: Used for amputating a limb; a large one is
used for amputating the thigh, a medium size for the leg, a small
one for the arm (Fig. 165).
Knife, tenotomy: A small narrow knife for cutting tendons under
the skin (Fig. 166).
Lachrymal probes: Small silver probes for introducing into the
tube or duct leading from the eye to the nose (Fig. 167).
Lachrymal styles: Button-headed silver instruments for passing
into the duct leading from the eye to the nose (Fig. 168). .
Lancet: An instrument used for bleeding, vaccinating, and open-
ing boils or small abscesses (Fig. 169).
Lavage tube, rectum: A large, soft-rubber tube for washing out
the bowel (Fig. 170).
Lavage tube, stomach: A large, soft-rubber tube for washing out
the stomach (Fig. 171).
Needle, aneurism: A curved, blunt instrument, with an eye near
the end, used for passing a ligature under an artery (Fig. 172).
Needles: (a) An ordinary suture needle; (b) a cervix needle;
(c) an intestinal needle; (d) a perineal needle. Needles are made
in a very large variety of styles and sizes (Fig. 173).
Periosteotome: An instrument for separating the periosteum from
bone (Fig. 174).
Probe: A silver-wire instrument for probing wounds (Fig. 175).
INSTRUMENTS AND APPLIANCES 221
Explanation of Figs. 176 to 181.
Retractor: An instrument for holding apart the edges of wounds
in operating (Fig. 176).
Saw, amputating: A saw used for sawing the bone in amputa-
tions of the limb (Fig. 177).
Saw, Hey's: A small saw for cutting a piece out of a bone;
used in operations on the skull (Fig. 178).
Sazv, metacarpal: A small, straight saw for dividing the meta-
carpal bones (Fig. 179).
Saw, plaster of Paris: For breaking and removing plaster band-
ages (Fig. 1 80).
Scalpel: A short knife with a convex edge, made in different sizes
and used for cutting and dissecting (Fig. 181).
INSTRUMENTS AND APPLIANCES
Explanation of Figs. 182 to 189.
Scissors: Straight (Fig. 182).
Scissors, curved: .Scissors having the blades curved (Fig. 183).
Scissors, bandage: For cutting bandages, etc. (Fig. 184).
Sound: A metal instrument for dilating stricture or examining
the bladder (Fig. 185).
Speculum, ear: A more or less conical cylinder for examining the
ear. Usually in nests of different sizes (Fig. 186).
Speculum, eye: An instrument for holding apart the eyelids (Fig.
Speculum, nose: A valved instrument for holding open the nostril
Sponge-holder: An instrument for holding sponges when operat-
ing in cavities (Fig. 189).
INSTRUMENTS AND APPLIANCES
Explanation of Figs. 190 to 194.
Speculum, rectal: For examination of the rectum (Fig. 190).
Spud and needle, eye: For removing foreign bodies from the eye
Searcher, stone: For ascertaining the presence of stones in the
bladder (Fig. 192).
Syringe, urethral: For applying solutions into the urethra (Fig.
Syringe, wound dressing: Also used for filling the bladder in con-
junction with soft-rubber catheter (Fig. 194).
INSTRUMENTS AND APPLIANCES
Explanation of Figs. 195 to 197.
Stethoscope: An instrument with which to listen to the sounds
of the chest (Fig. 195).
Syringe, hypodermic: A graduated glass or metal syringe fitted
with a hollow needle, employed in the injection of morphine and
other medicines beneath the skin (Fig. 196).
Tenaculum-Forceps: (Fig. 197).
INSTRUMENTS AND APPLIANCES
Explanation of Figs. 198 to 200.
Thermo-cautery, Paquelin: A cautery in which the fuel is incan-
descent benzine (Fig. 198). <r
Tongue depressor: An appliance for holding down the tongue
in throat work (Fig. 199).
Tonsillotome: An instrument for removing the tonsils (Fig. 200).
INSTRUMENTS AND APPLIANCES
Explanation of Figs. 201 to 205.
Tourniquet: An instrument for making pressure on an artery
to stop the flow of blood through it (Fig. 201).
Tracheotomy tubes: Two curved silver tubes, one fitting inside
the other, used for putting into the wind-pipe when it has been
opened by an operation called tracheotomy (Fig. 202).
Trephine: A circular saw used in operations on the skull (Fig.
Trocar and cannula: A sharp pointed instrument and sheath for
tapping collections of fluid (Fig. 204).
Truss: An appliance used in the treatment of rupture (Fig. 205).
INSTRUMENTS AND APPLIANCES 233
Explanation of Figs. 206 to 208.
Beside the above there are certain special apparatus and cases :
Apparatus, compressed air: This consists of a metal air container,