bacteria and their life processes may be followed with comparative ease. Much of the advanced knowl- edge of human structure, needs, and functions has been gained through their aid, and the recent dis- coveries in connection with malaria and yellow fever have brought them into prominence in other than scientific circles. The terms microbe, germ, or micro- <Callout type="important" title="Important">microorganism</Callout> are applicable to the protozoa as well as to bacteria. Unlike harmless protozoa, there seems to be no record of especial good to their credit.
The transmission of disease All infectious diseases are supposed to be trans- mitted by the agency of one or the other of such living agents in infectious bodies; though their presence has been proved, the specific germ causing the disease has been recog- nized and actually cultivated outside the body in com- paratively few instances. The disorder begins with the introduction of the germs into the system, progresses with their develop- ment and multiplication, which is almost inconceiv- ably rapid, and terminates with their destruction when Nature is able to accomplish it, or with the death of the patient when they are victorious.
The bacterial source of typhoid fever, tubercu- losis, pneumonia, Asiatic cholera, lockjaw, and other less familiar diseases has been proved, and the modern methods of prevention and cure are based on what is known of the condition under which bacterial life thrives or is destroyed. The demands which physicians make that their patients shall have sunlight and fresh air, the methods <Callout type="tip" title="Tip">Enemies of Disinfection</Callout> employed in infectious diseases are rational, because science has found that germ life flourishes best in warm, dark media, that sun and air are its worst enemies, that continued heat, of boiling water in some cases, and of condensed steam in others, destroys it, as do also certain so- called disinfectants.
The protozoa The consideration of the protozoa as an agent in <Callout type="risk" title="Risk">Protozoan Infections</Callout> infection has come into prominence through investi- gations made regarding the part played by insects in disease propagation. These investigations, with experimentation, have been carried out mainly in re- gard to mosquitoes, and the results have established beyond question the fact that the prevalence of mala- ria in certain districts is referable to the presence of these insects rather than on account of climatic con-, ditions pure and simple, and that the protozoa dis- covered in the stomachs of mosquitoes found in such districts are of the same variety as those found in the blood of malarial patients. The numerous experiments which have led to these conclusions are given in an article in the 'Popular Science Monthly' by Professor A. F. A. King, M. D., entitled 'Mosquitoes and Malaria,' and in books upon the same subject by the same author.
Disinfectants The following agents for disinfection, together with the general scheme for their use, are recom- mended by the Board of Health of New York City: Sunlight, cleanliness, and fresh pure air are pow- erful preventives of disease, and play an equally im- portant part in their cure, but in dealing with cases of infectious disease the aid of agents known as dis- infectants must also be called in. After such disease, and also during its course, all the articles of small value which have been used in contact with the patient in any way should be de- stroyed by fire. Dishes, silver and metal objects not injured by water may be made thoroughly sterile by boiling in a closed vessel for half an hour, and in cities large articles, such as bedding, can usually be taken care of by the Health Department. A five per cent solution of carbolic is a very power- ful disinfectant to be used on clothing, towels, bed- ding, etc. It is made by dissolving six ounces of the acid in a gallon of hot water. The pure acid is a very strong corrosive, and even the five per cent solu- tion is too strong for use on the hands. If a person is burned with carbolic, pouring alco- hol over the cauterized surface gives instant relief. It is very poisonous when taken by the mouth, should have a poison label plainly upon it, and should be kept out of the reach of children.
Solution of corrosive sublimate is easily made with tablets, which are dissolved in water. Directions are found on the bottles. It is much less expensive than carbolic acid, but is not as useful. It injures metals, stains clothing, and is not effective in the disinfection of discharges, because it merely incloses the particles which it touches in an albuminous coating; its action on albumen being to cause it to coagulate. In this way the germ is preserved, but not destroyed. It is useful in cleaning woodwork and furniture.
Chlorinated lime solution is one of the most effect- ive as well as least expensive disinfecting agents. It is prepared by thoroughly mixing six ounces of fresh chloride of lime with one gallon of water. It should be made only about an hour before using. The danger of using this on bedding, clothing, etc., is that it tends to destroy the fabric. If it is employed it should be thoroughly strained through a cloth and diluted one- half.
Milk of lime is equally valuable. The solution is made by adding a quart of finely slaked dry lime to four or five quarts of water. It should be remembered that air-slaked lime has lost its disinfecting power.
Formaldehyde gas is a very powerful disinfectant, commonly used now in the general fumigation of rooms after contagion. The strongest liquid prepara- tion on the market is the forty per cent solution of this gas in water. The five per cent solution is effective for the disinfection of discharges, and of dishes, instru- ments, etc., and a one per cent solution may be used on the hands. Formalin is so expensive that it is rare- ly thought best to use extensively in the household, but its action is so powerful that it is taking prece- dence over other disinfectants when expense need not be considered.
FORMULA Formalin, 5 per cent : Strong formalin, 5 parts ; water, 35 parts. Or, Formalin, 5 per cent : 4.75 ounces formalin to one quart of water. Formalin, 1 per cent : Strong formalin, 1 part ; water, 39 parts. Or, Formalin, 1 per cent : .95 ounces to one quart of water. Formalin, 1-5000 : Strong formalin, 1 part ; water, 2,000 parts. Or, Formalin, 1-5000: 10 drops of strong formalin to one quart of water.
Another preparation used in fumigation is gas from burning sulphur. This is not regarded with as much confidence in recent years as it was before the wonder- ful vitality of disease germs was understood. The advantages of the method are that the fumes are very diffusible, they do not injure furniture, are easy to use and are not expensive. The difficulty in the use of sul- phur is in confining the gas in a room for a long enough time to destroy the germs. Three pounds of sulphur for every thousand cubic feet of air space is necessary, the room must be tightly closed, and all cracks where air might enter must be sealed, by pasting strips of paper over them. It is more effective if burned in a moist atmosphere, so the usual method is to place the dish holding the sulphur on rests in a vessel containing water. It must be re- membered that the fumes blacken metal, and that a liberal application of vaseline will prevent this action. The bacteria of tuberculosis are able to protect themselves from destruction by sulphurous gas by a change in their structure, therefore some other method of disinfection is necessary after this disease.
If formaldehyde gas is available it should always be given preference in fumigation. In disinfec- ting METHODS OF DISINFECTION The formalin solution one per cent or the carbolic solution diluted with an equal part of water is to be used on the hands. The dry chloride of lime is also of value. If the liquids are used, the hands should be thoroughly washed in the solution and then with soap and water. Especial care should always be given the nails. About a teaspoon of the dry chlo- ride of lime is placed in the palm of the hand, moistened with water, and rubbed thoroughly all over both hands and about the nails.
Any disinfectant is irritating to the skin if used for any length of time. It is not only the feces, but also the discharges from bladder, mouth, and nose, which must be disinfected or burned. Expectoration and discharge from the nose may be received upon cloths or paper and must be burned at once. When vessels are used, a solution of lime or carbol- ic acid must be kept in them, and after use the con- tents must be mixed with the disinfectant and allowed to stand for an hour or more. If carbolic is used, the amount should be twice that of the discharge, with milk of lime four or five times as great.
All discharges must be broken up so that the disinfectant will be thoroughly mixed with them. They are not disinfected if the solution is merely poured over them. In typhoid fever, the discharges from the entire digestive tract and from the bladder are regarded with suspicion, and subjected to the action of the disinfec- tant. In dysentery and cholera, the stool and vomited matter contain the poison, and in diphtheria, scarlet fever, and measles the discharges from the nose and throat carry the infection.
Germs are not scattered while the medium in which they are contained is kept moist. The food which is left after the patient has been served must never be taken back to mix with the garbage from the household. It should be put in a sep- arate covered receptacle, and either burned or sub- jected to the action of a disinfectant. Bacteria thrive especially on milk, and therefore milk should never be left uncovered in the sick-room.
In any disease, food should be kept outside the sick- room, since it is very liable to become contaminated. All washable articles must be put to soak in either a carbolic or lime solution, and left for ten or twelve hours. They can then be washed in the usual way. The boiler containing the disinfectant should be kept in a room adjoining the sick chamber, and should not be removed till after disinfection is complete.
A pint of carbolic solution or of milk of lime solu- tion should be poured into the closet each time after using. Nothing should be thrown into it or into sinks without disinfection. If it could be assured that it would remain moist and would be held intact in the sewer pipes there would be no danger, because the germs could not be disseminated and the action of other bac- teria would in time render them harmless. Accidents, however, do occur in sewer pipes, and since a leak can give rise to an epidemic of disease, every precau- tion must be taken to guard against the deposition in the pipes of living germs where it is possible.
During sickness, the cleaning and dusting must be done with cloths wrung: out of a 10,000 bichloride solution of <Callout type="tip" title="Tip">Disinfection of Furnishings</Callout> furnishings. At its termination, if the Health Department has an effective sterilizing plant, all bedding, carpets, cur- tains, etc., can be removed and made entirely germ- free, and it is always advisable, when it is not compul- sory, to have the fumigation carried on by the Depart- ment. In country places, this responsibility must be assumed by the family, and if they are conscientious about it, they can accomplish it effectively.
The wisest plan in contagious diseases is to strip a room of woolen curtains, carpet, and unnecessary ornaments, and to bring into it for the patient's use and amusement only such things as can be burned or boiled at the termination of the disease. Formalin seems to be the most practical disinfec- tant, and knowledge of certain facts concerning it will make our use of it rather more intelligent. In order infectant <Callout type="important" title="Important">to exert its destructive action on micro-organisms</Callout> it must have, first : free access to them — hence all cloth- ing, curtains, etc., which are left in the room for disin- fection must be hung up or spread out so that the entire surface is exposed. Second : it must be concentrated as far as possible, that is the room must be sealed to hold the vapor, and more formalin, and a longer time is necessary if there is any appreciable escape of gas from an apartment. Third : the higher the temperature the more effec- tive and more penetrative is the action of the formalin, therefore the room should be heated either by turning on heat from furnace or boiler, or by building a fire in stove or heater. Fourth : a moist atmosphere is conducive to more thorough fumigation, i.e., steam should be allowed to escape into the room in order to get the best possible results.
A space represented by 1,000 cubic feet is supposed to require from two to three fluid ounces of formalin and five to eight hours' exposure. An especial apparatus is used by the Health De- partment, bv which the formaldehyde gas is generated outside the apartment, and introduced through the keyhole till the required amount has passed in, when the pipe is withdrawn and the keyhole sealed.
Household fumigation must be accomplished with- out the use of special appliances and can be done as fol- lows : The room should be carefully sealed, the temper- ature raised as high as possible with safety to it and its contents, and if possible steam should be allowed to escape into it. If the heat of the room is maintained by the use of a stove, a large tea-kettle or boiler of water may be kept boiling. Care must be taken to pro- vide sufficient water for the entire length of time. An alcohol lamp may be placed in the centre of the room, quite away from furniture, on a metal plate, so that there can be no possibility of its tipping over. The forty per cent formalin, three fluid ounces, should be placed in an open vessel and put oyer the alcohol lamp. It is estimated than two ounces of alcohol will be required to generate the fumes of this amount of formaldehyde. After the lamp is lighted, the person who has charge of the fumigation must quickly leave the room, and seal the door.
The nature of the bacteria makes a difference in the amount of disinfectant, and the length of time re- quired,
Key Takeaways
- Disinfection methods are crucial for preventing disease spread in homes.
- Formaldehyde gas is recommended as a powerful disinfectant, but it requires careful handling and sealing of the room.
- Sunlight, fresh air, and cleanliness play important roles in disease prevention.
Practical Tips
- Use formalin or carbolic acid solutions for hand washing during infectious diseases to prevent spreading germs.
- Regularly disinfect surfaces and clothing that have come into contact with sick individuals to reduce the risk of infection.
- Keep food outside the sick room to avoid contamination, especially in cases like typhoid fever where fecal matter can spread disease.
Warnings & Risks
- Be cautious when handling strong disinfectants like carbolic acid, as they are corrosive and poisonous if ingested.
- Avoid using sulfur fumigation methods for tuberculosis due to the bacteria's ability to protect itself from destruction by this method.
- Ensure proper ventilation during formaldehyde gas fumigation to avoid inhaling harmful fumes.
Modern Application
While many of the disinfection techniques described in this chapter are still relevant today, modern methods have improved in terms of safety and efficiency. For instance, while sunlight and fresh air remain effective natural disinfectants, specialized chemical treatments and UV sterilization offer more targeted and rapid results. Understanding these historical practices can provide valuable context for developing comprehensive home hygiene protocols.
Frequently Asked Questions
Q: What are the main methods of disinfection mentioned in this chapter?
The main methods of disinfection discussed include formaldehyde gas, carbolic acid solutions, chlorinated lime solution, and milk of lime. These were recommended for use on clothing, bedding, and other surfaces to prevent disease spread.
Q: Why is it important to keep food outside the sick room during an infectious disease?
Keeping food outside the sick room prevents contamination from discharges such as feces or vomit. This reduces the risk of spreading diseases like typhoid fever, where fecal matter can be a source of infection.
Q: How should formaldehyde gas fumigation be performed?
Formaldehyde gas fumigation requires sealing the room to hold the vapor and heating it with a stove or boiler. The room temperature should be raised, and steam can be allowed to escape for better results. A specific amount of formalin (three fluid ounces) is placed in an open vessel over an alcohol lamp, which generates the required gas.