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CHEMICAL DISINFECTION

Why is it that the fly, the mosquito, the bedbug, and the body louse are under the ban as known or possible carriers of infection?

What is meant by disinfection?
Why is disinfection necessary?

How many kinds of disinfection are there? What determines the method to be followed in a particular case?

These and other similar questions are suggested by the fact that cases of infectious disease are apparently increasing, and that we are advised to boil the water, drain the marshes, and disinfect.

In some cases a chemical is recommended, and in others heat, light, or other physical agents are applied; while in still other cases the use of a vaccine or serum iş considered of first importance and the others secondary.

The more dense the population, the more care is necessary to prevent the spread of disease. The more filth present, the more rapidly do insects multiply to aid in the spread of disease. While no disease is directly due to filth, filthy conditions are conducive to many diseases. Because we do not actually see the conditions it is only with difficulty that we can be brought to realize the danger.

THE NECESSITY IS APPARENT.

We are ordinarily on guard only when we see, or actually know of, the source of infection. The fly that walks over our dinner plates. may have come directly from exposed excreta of a case of enteric fever, the dust we inhale on a windy day may be the dried sputum of a diphtheria or tuberculosis patient, but our ordinary sensations are discomfort only. One rarely thinks seriously of the possible danger or of the filth from which they were derived.

The necessity for rigid disinfection of all recognized sources of infection is therefore very apparent. For if the flies have no infectious material to walk over they will carry no infection, and if no feces or sputum is allowed to dry unsterilized and be carried by the winds, the dust will not be very dangerous. This, however, is a glimpse of Utopia which may never materialize, for it is only by the strictest

By H. C. HAMILTON, M.S.

supervision that the average man will take thought for his neighbor.

Diseases are largely contracted from air, water or food contaminated by diseased persons, or from direct or indirect contact with an infectious disease.

Disinfection is necessary to prevent the spread of the disease from one person who has an infectious disease to others; that is, to kill the organisms before they can be carried to others.

This may be done by burning all excreta or applying such a degree of heat as to destroy the infectious organisms, or it can be in many cases more easily accomplished by means of chemicals. Every precaution should be taken to safeguard the healthy.

The fly carries bacteria on its feet, the mosquito carries the material parasite from a patient to a healthy person in sucking blood, and the body louse is the incubator for the typhus organism. The bedbug is merely under suspicion, no proof that any specific disease is carried by it having yet been discovered; but everything, animate or inanimate, which goes from the sick-room is to be regarded as a possible means of spreading disease.

Bacteria are never found unassociated with other organic matter, and this should always be considered as an important factor in the problem of disinfection. The kind of bacterial contamination, too, must not be lost sight of, since the relative resistances of different organisms differ greatly.

CARBOLIC ACID AND CORROSIVE SUBLIMATE. Two standard disinfectants come to mind at once when the need arises, namely, carbolic acid and corrosive sublimate. These, however, have certain serious disadvantages, such as their toxicity and their property of coagulating tissues.

The danger from poisoning is only through intent or by mistake, and in well regulated homes may be disregarded. But both substances are convenient and efficient for suicidal or murderous purposes and could with profit be replaced by some other disinfecting agent.

There are few instances in which some other substance is not applicable either with equally good or better results.

When carbolic acid is applied in its strongest solution the skin or tissue with which it comes in contact is destroyed, unless the acid is instantly diluted. This coagulated tissue is almost proof against the immediate absorption of liquids, so the surface layer, only, is disinfected.

To a lesser degree the same is true of corrosive sublimate, which, as its name implies, is an active corrosive agent, both to metals and to tissues. It corrodes metals by an interchange which dissolves the steel or nickel and deposits mercury. It corrodes tissues because of its inherent property of combining to form practically insoluble and inert proteid compounds.

The coagulating action of mercuric chloride can, however, be avoided by the use of mercuric iodide, preferably in the form of soap and tablets. The latter salt, when in solution, is about 5 times as strongly germicidal as the chloride, and when associated with appropriate substances is not corrosive to metals and is not a coagulant, its bactericidal action being due entirely to the formation of a combination toxic to the bacteria.

A DESIRABLE FEATURE.

This association with soap enhances rather than detracts from its value, as is the case when mercuric chloride is mixed with soap. In fact, the presence of an alkali, either free, as in the germicidal discs, or one which becomes free through hydrolysis, as in the soap, is one of the desirable features in a disinfectant, since the solution is then similar in character to the plasma.

It is less irritating and more easily penetrates to poison the bacteria.

The expert sanitarian, however, is making use of a variety of disinfectants, each adapted to its particular use. The sterilization of sewage is carried out differently from the disinfection of stools at the bedside. The latter is accomplished by use of chemicals, the other by a biologic process in which non-pathogenic bacteria outgrow and destroy the pathogenic types. The object is disinfection, but the method and the substances used are varied to suit conditions.

Bacteria are never found unassociated with

other organic matter a fact which should always be considered as an important factor in the problem of disinfection.

Diseases are spread largely by direct or indirect contact with a patient, by insects, and by ingestion with food or drink. The first of these is the method of infection which can best be controlled by chemical disinfectants.

The control of insect pests which spread disease has reached a point where certain diseases have been practically eliminated in certain localities which had become almost uninhabitable. The spectacular results in controlling malarial, typhus and yellow fevers in man, and the Texas fever in cattle, show what possibilities there may be when the mode of infection is known, even though the infecting organism has not been recognized.

The Federal, State or municipal control of conditions surrounding the production and handling of our food and drink supplies, while partly responsible for the high cost of living, is frequently all that stands between us and infinite danger.

GASEOUS DISINFECTION.

Although formaldehyde is naturally a gas, its most familiar commercial form is a 40-percent aqueous solution. Its most efficient form as a disinfectant also is in aqueous solution, the dry gas being without material action on bacteria or vermin. This statement seems to be in contradiction to the most common use of formaldehyde, namely, as a fumigant, or gaseous disinfectant. The accuracy of the statement has, however, been established by bacteriologists, and this fact is undoubtedly the reason for many failures in disinfections with this valuable agent.

Experiments carried out by the Pennsylvania Railroad in disinfecting cars proved that if the air carries 70 per cent of the moisture required to saturate it, and if a sufficient quantity of a 40-per-cent solution of formaldehyde is used, thorough disinfection always results, regardless of the temperature.

There are three essentials to the successful disinfection with formaldehyde:

1. Use not less than 1 pint of a 40-per-cent solution to each 1000 cubic feet of space to be disinfected.

2. By a preliminary sprinkling of the floors with water, bring the air of the room or building almost to the saturation point of humidity.

3. Avoid attempts at disinfection on a windy day. It is almost impossible to hold the vapors in the room long enough for efficient action. The vapors must be rapidly set free from the solution.

Failures in disinfection with the consequent discredit into which it has fallen with many sanitarians is largely due to lack of proper attention to those details. It is also partly due to the natural question as to how much reinfection occurs from the objects in the sickroom, or whether all the danger is not either directly or indirectly from the patient alone.

This is still a disputed question, but even those who incline to the belief that infection. from objects in the sick-room very rarely can occur are not ready to eliminate all disinfection, but suggest as a substitute a thorough scrubbing with soap and water instead of tumigation with formaldehyde. This is undoubtedly very efficient for the surfaces covered, but can never reach every point, as formaldehyde does.

BY CHEMICAL ACTION.

Formaldehyde gas can best be set free from the solution by chemical action, such as that by permanganate or dichromate. This method destroys a small part of the agent, but brings about rapid evolution of the gas and water vapor-two important conditions.

Lime is an effective disinfecting agent only if it is fresh and unslaked, since its value is in the heat generated when brought into contact with warm water, the germicidal value of the lime water being almost negligible. Copper sulphate has been found an exceedingly satisfactory disinfectant for the renovation of the water of swimming pools, but its low power as a bactericide would indicate that whatever extraordinary value it possesses cannot be discovered by ordinary laboratory test.

The common coal-tar disinfectants are effective in proportion to their phenol coefficient; they owe their germicidal value to the phenols contained. These are compounds closely related to carbolic acid, or phenol proper, which are formed during the process of manufacturing coke or gas from bituminous coal.

By subsequent chemical treatment there is obtainable a series of phenols differing among themselves in chemical and physical characteristics, in toxicity and in bactericidal value.

In many respects these approach the ideal as disinfectants, if one appreciates the fact that an objectionable characteristic in a certain disinfectant becomes, under other conditions, its most desirable feature. For example, entire volatility and solubility are commendable in formaldehyde, but for disinfecting stables, pens and cars, these features are disadvantages from which one would turn away without hesitation.

DISTINGUISHING POINTS.

The phenols of coal tar are not reducing agents, like "copperas," which as readily takes up oxygen from the air as from bacteria.

They are not oxidizing agents, like "chloride of lime," which gives up its oxygen to live or dead matter indiscriminately.

They do not appear to produce chemical compounds with protoplasm, as does mercuric chloride—a combination which for a limited time acts as an inhibiting agent only.

They do not in general precipitate or coagulate the organic matter when they come in contact with it, and so become self-limiting in action.

They are relatively non-toxic to animal life and non-irritating to tissues, when appropriately diluted for use.

These last two features (which may or may not be objectionable in a disinfectant) are reduced to a minimum in certain coal-tar products of this series, but are present in the two most commonly used and best known, namely, phenol proper, or carbolic acid, and cresol, or cresylic acid.

These two are less affected by the inhibiting action of the organic matter which invariably accompanies bacteria and more readily penetrate masses of organic matter which would filter and tend to remove the globules of an emulsified disinfectant.

THE USE OF SOAP.

The less soluble phenols, which are usually associated with some of the neutral oils of coal tar, are rendered easily soluble in or miscible with water by an agent which partly dissolves and partly emulsifies the active agents, namely, soap. Soap, in and of itself, is of very slight germicidal value, but associated with these highly germicidal but insoluble phenols it makes them readily miscible with water, increases their penetrating power and

removes the grease and dirt which would otherwise tend to inhibit the action of the disinfecting agent.

The phenols of coal tar, therefore, offer to the sanitarian a diversity of products with phenol coefficients ranging from 1 to 20, with toxicities from 100 per cent to 10 per cent, some soluble, others in emulsified form, and with nothing left to guesswork as to their efficiency or applicability.

While it is true that the germicidal value is determined by a laboratory test which does not duplicate practical working conditions, the phenol coefficient can with assurance be used as the multiplier to find the dilution comparable to any specified dilution of carbolic acid.

For example, since the latter is commonly used in 5-per-cent solution, or diluted 1 in 20, a disinfectant with coefficient of 2 can be used diluted 1 in 40 with entire assurance that it will be equally efficient. Much of the discredit from which the coal-tar products have suffered can be traced to the fact that many of them have been placed on the market without standardization, and with extravagant claims regarding their efficiency-claims which on careful examination could not be substantiated.

The value of the coal-tar products as disinfectants now rests on a sure foundation. A good one properly used will go far towards safeguarding the health of the family and the community.

OBVIOUS LEAKS
THAT ARE OFTEN IGNORED

Probably the greatest uncalled-for leak in a drug store is caused by giving overweight. The proprietor or clerk is liable to acquire the habit of adding just a little more after the scales have been balanced, of not taking overweight out of the pan after it has gone down. The excuse for this carelessness may be that the article does not cost very much; and such a contention may be true, in a way. But it is a sort of continued story when this practice is kept up for a year. A bad and wasteful habit is formed, and sometimes high-priced articles are treated just as carelessly.

It may sound foolish to some to suggest economizing in wrapping paper, but those who have kept track of losses in this matter do not think so.

Many drug stores throw away bottles which have contained fluidextracts, tinctures, etc., probably because they are a little hard to clean or because of the waste of time it would require to clean them. These bottles do very welljust as well as any other, in fact for such things as wood alcohol, spirit of turpentine, carbolic acid, and so on. A neat little sum may be saved in this manner in a year.

It seems needless, too, to caution the average druggist or clerk in regard to corking the alcohol can or barrel after he has drawn off a gallon or two of this very volatile and rather expensive liquid, but if any one man could

By HAROLD C. BARR

receive for vacation money what is lost in this way every year, his play spell might extend throughout the balance of his natural life.

The proprietor, especially, should be careful in this particular. His example is followed by the clerks.

We are all aware of the fact that much of the secret of success is associated with the continual turning over of the stock, and that it is very necessary to get rid of stickers and dead ones. The stock must be kept clean, not only of dirt and dust, but also of goods which are all · too often put in the stock-room and then never seen again until inventory time comes around. And right here let it be said that a successful business man takes an inventory at least once a year.

Some stores waste money by advertising injudiciously. These cases, of course, can only be remedied by going against the game and profiting by adverse experiences. The experiences of others should be eagerly sought for, also.

The advertising expense of many drug stores might be lessened if they would use persistently and carefully the booklets and leaflets which nearly all manufacturing firms send out. Much of this material is good and will reach its mark if properly directed.

Drug-store economy may not spell wealth, but it will help some.

Money-makers and Money-savers.

Information as to where any of the articles mentioned in this department may be obtained will be furnished upon application. Address "Department of Money-makers," THE BULLETIN OF PHARMACY, Detroit, Mich.

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