Even before the discovery of the tubercle-bacillus by Koch, different scientists had claimed that pulmonary consumption was caused by the immigration of bacteria into the lungs, and several of them had found bacteria of that kind. But it remained for Koch to bring light upon the conjectures of other scientists, and he established the fact, that the bacillus discovered by him was the real generator of pulmonary consumption. Millions of these bacilli exist in the lungs of the diseased, and millions of them are thrown out with the sputum.

If we take a very small quantity of this thrown out matter and examine it with a microscope, we will find a greater or smaller number of these tubercle bacilli. Of course the preparation to be microscopically examined must previously be colored with some coloring matter, otherwise it is very difficult, well nigh impossible, to detect the infinitely small bacilli. The method of coloring now generally in use consists in discoloring the preparation after the coloring has been completed, it is found that the bacilli tenaciously cling to the coloring matter, and in this way it is easy to recognize the tubercle-bacilli under the microscope.These bacilli are infinitely minute, they are ²/₁₀₀₀ to ⁸/₁₀₀₀ millimeters long, and about ⁵/₁₀₀₀₀₀ millimeters in width. Therefore it is absolutely impossible to recognize them with the naked eye. Generally they are somewhat bent, sometimes slightly nicked at one end.

The temperature of boiling water destroys the vitality of the bacilli under all circumstances. Even a temperature of 70°C. is able to lessen the efficacy of the bacilli. Unhappily this temperature is too high to be applied against the tubercle-bacilli in the human body without causing the most serious injury to it. Nevertheless it has been tried, we will speak of this later on.

Then the drugs that kill the bacteria, such as Carbolic Acid, Alcohol, Iodoformether, Ether, Sublimate, Thymol, destroy the tubercle-bacilli so slowly and only in such high concentrations that their application is impossible without endangering the patient. Therefore the prospects of directly destroying the bacilli in the human body had to be given up as impossible.

We are now confronted with two questions:

All investigations, both of earlier and later date have established the fact that the tubercle-bacillus is inhaled with the air, and then it is mainly the foul air which is accused. But foul air is especially found in such places where people congregate, as in rooms, barracks, factories, etc. As it is a fact that there are always several consumptives among a number of people, so in this case there will always be occasion to inhale the tubercle-bacilli that have been cast out by the consumptives. Therefore it is not the foul air in itself which generates pulmonary consumption, but the circumstance that in this connection there are always people present which are able to spread and scatter the bacilli.

Luckily the physical qualities of the tubercle-bacilli are such that they mostly adhere to the ground or floor and are rarely scattered in the air as dust; otherwise pulmonary consumption would be much more frequent than it is at present. Unfortunately the bacilli are very often spread through uncleanliness of the people, because they touch objects with their fingers to which the tubercle-bacilli chance to stick and then they touch their mouth or nose with these fingers. In this way bacilli can be taken into the system especially easily with the food. Children are particularly exposed to contamination, crawling about on the ground, on which, perhaps but recently, a consumptive has spit, and more so because they often have the habit to put all sorts of things and also the generally dirty fingers into their mouth.

On the other hand there are various obstacles in the way of tubercle-bacilli entering the lungs. The distance from the mouth to the lungs is long and narrow; all sorts of projections check the further penetration of the bacilli. The trachea and the air-passages of the lungs possess equipments arranged for the purpose of ejecting small foreign substances, thus also to throw out the bacilli. In short it is not too easy a matter for the bacilli to penetrate into the lungs.

And yet this happens only too often. For instance, in some people the passage from the mouth down may be a wide one, so that the bacilli can enter more easily; the protective arrangement by which foreign substances are removed may be deranged, it may be wanting in some place or its functionary qualifications may be bad; especially frequent this is the case after enfeebling diseases, which are associated with severe cough, as measles, whooping-cough, etc. This is the reason why pulmonary consumption is strikingly often observed to follow just these diseases.

But the tubercle-bacillus can also enter the body with the food, as stated before. The acid gastric juice is a protective agent which considerably lessens the danger of infection by tuberculosis.It has not been definitely decided at the present time whether the drinking of milk from tuberculous cows brings with it the danger of tuberculosis for mankind. It will certainly be best to avoid such milk, especially when the cow's udder is found to be tuberculously diseased or when tubercle-bacilli can be traced in the milk.

The use of meat as food may also become dangerous to man, but this is a rare occurrence. It is particularly dangerous to eat the liver, kidneys and lymphatic glands of tuberculous animals. The boiling heat while cooking generally destroys the bacilli contained therein and so lessens the danger from this source. It is of no little importance, to call particular attention to the fact that our chickens are very often severely infected with tuberculosis.

The question, whether a consumptive can infect his surroundings, may be answered thus, that this does not happen as a rule. Several unhappy circumstances must come together to make this possible. Above all things a direct transmission of tubercle-bacilli in some way into the body of the healthy person, then the bacilli must cling and propagate in the same, which is only possible when there is an inclination to this disease, of course this inclination is quite common.

Pulmonary consumption is not hereditary in the strict sense of the word. Only an inclination to this disease is transmitted. As the danger of contagion of those having such disposition is very great, so as a rule the disease makes its appearance sooner or later.

On the other hand it must be considered that the penetration only of the tubercle-bacilli into the body is not sufficient to generate tuberculosis. If they do not find the ground adapted to their nourishment and propagation they perish. It may be assumed that every person is placed in such circumstances at some time that he will take in tubercle-bacilli; but only a certain percentage will get consumption. In the remainder the bacilli perish without leaving even a trace.

Very often the inclination to pulmonary consumption may be recognized from the external characteristics. As a rule the respective individuals have a slight body, thin lean skin, weak muscles, delicate skeleton, a long, narrow, flat chest, flattening of the regions over and below the shoulderblades, wide intercostal spaces, a winglike projecting of the scapulÆ, long neck, clubby, knoblike appearance of the ends of the fingers.

Furthermore it has been found, that pulmonary consumptives on an average have a smaller heart than is essential to a healthy body. On the other hand the volume of the lungs of consumptives is very often abnormally large.There are a large number of diseases that predispose to pulmonary consumption. It is mainly the enfeebling action of the same, which brings about such results. For this reason the chronic diseases contribute so much toward the multiplication of the number of consumptives, because they stipulate a continuous weakening of the organism and an emaciation of the system. To these belong Bright's disease, which very often turns into pulmonary consumption, greensickness or chlorosis, anaemia, continued febrile diseases, severe chronic suppuration, chronic catarrh of the stomach, frequent pregnancies, childbed diseases. Thus we may often see young chlorotic girls afflicted with consumption, especially when they marry young and enjoy the honeymoon to its utmost limits. Then also women will easily become consumptive when they give birth to a child every year, especially when the social conditions in which they live are of an unfavorable nature, and they are perhaps inclined to consumption already. Childbed on the whole inclines to arousing the dormant inclination toward pulmonary consumption.

Of other diseases we have mentioned measles and whooping cough, as diseases that are only too easily succeeded by consumption. To these may be added typhus, especially when it is of a more protracted nature, and the reconvalescence is slow and incomplete.Furthermore all those workmen that have to do with dust, are exposed to the danger of being stricken with pulmonary consumption. The dust enters the lungs, irritates and injures the same and so produces a favorable soil for any tubercle bacilli that may happen to penetrate. On the whole metal dust is more injurious than mineral dust. Workmen, that are exposed to animal dust, as furriers, saddlers, brushmakers, fall prey to consumption much oftener than those, that fulfill their vocation in air pregnant with vegetable dust. According to statistics workingmen are stricken with pulmonary consumption as follows: of glass workers 80 per cent., needle grinders 70, filemakers 62, stone cutters 40, mill grinders, lithographers, cigarmakers, brushmakers, stone-polishers 40–50, millers 10, coal workers 1 per cent.

Pneumonia may culminate in pulmonary consumption: but on the whole this rarely happens. Much oftener it is the case with Pleurisy. But it is assumed and rightly, that most people who are attacked by pleurisy, are already consumptive.

A hemorrhage of the lungs may nearly always be considered a sure sign that consumption has taken hold of the respective individual; but such a hemorrhage certainly forms considerable danger to falling a victim to tuberculosis, if the individual is as yet free from the same.Age has a particularly decided influence on the origin of consumption; it is extremely rare before the third or fourth year, from that to the seventh it is more frequent; it most frequently occurs in the age from the fifteenth to the thirtieth year, and from there on the chances are again fewer. In very old age it is again very rare.

There seems to be no essential difference as regards sex.

Insufficient or defective nourishment acts as a promoter in various ways. Even the nourishing of infants with poor milk, with bread or flour-pap increases the disposition to pulmonary consumption. If this defective nourishment is continued, scrofula will surely follow and this is a stage antecedent to consumption.

Pulmonary consumption is relatively more frequent among the poorer than the well to do people, this is partly due to the meagre and scanty food of the poorer, and that they are obliged to subsist almost exclusively on vegetable diet. The higher the meat prices rise and the less the majority of the people can afford to procure meat, the larger will be the number of consumptives. The poorly nourished offer a good soil for the tubercle bacilli in consequence of their weakness. The tissue offers little or no resistance to the growth of the bacilli, these propagate and destroy the powerless and yielding organism with fearful rapidity.The frequency of pulmonary consumption increases with the size of the cities, or, which is the same, with the number of proletarians. Extreme hunger and want are less frequent in the country than in the city.

That the climate has an important influence on the appearance of pulmonary consumption has long been known. In certain elevated regions this disease seldom or never appears. This experience has been attained in Switzerland and many other mountain regions. Furthermore the Plateaux of Peru and Mexico are considered free from consumption, but also lowlands like Iceland, the Kirgheez steppes and the interior of Egypt are known to be exempt.

Damp and windy climate, especially with very high temperature, or abrupt changes in the temperature promotes consumption; on the other hand it is less frequent in the more moderated climates, especially if they are dry.

Now when the tubercle bacilli have settled in the lungs, they cause various symptoms. One of the most frequent is cough. In the beginning of the disease a short, clear but light, very often dry cough appears. During the further development of pulmonary consumption the cough becomes more periodic; it appears early after awaking, in the afternoon after dinner, and evenings at lying down; it may disappear entirely in the meantime or may be light only; but then as a rule it is no longer dry, but may be attended by expectorations of a varied nature.

The tubercle bacilli destroy the lung tissue and change it into pus, which is coughed out. In this way larger and smaller cavities are formed in the lungs; finally the cavities may even take more space than the remaining lung tissue. When cavities have already been formed, coughing comes easy and with abundant expectoration. Toward the end of life the coughing and spitting stops as a result of the extreme feebleness and weakness.

The violence and frequency of the cough depends mainly whether the larger bronchial tubes and the trachea are affected; the more this is the case, the more violent the inclination to cough. Further the strength of the cough depends on the excitability of the patient; the greater this is, the more as a rule will he cough. Sometimes the position of the patient is of influence; if he lies mostly on the diseased side the expectoration becomes more difficult and coughing increases.

Coughing is generally that symptom which soonest attracts the attention of the patient and his surroundings. For that very reason consumption is in its beginning stages easily confounded with such other diseases as are also accompanied by cough.At the same time we know of exceptional cases where cough was entirely absent in the first stages of the disease, or was at least so slight that it was overlooked, and under such conditions the pale and poor appearance and reduced strength is mistaken for chlorosis or some other anaemic affection, also the existing febrile excitements are wrongly judged, or on account of lack of appetite or light derangements of the stomach a stomachic affection is surmised, until suddenly a hemorrhage of the lungs clearly defines the true nature of the ailment.

On the other hand the cough may become so violent that vomiting is caused at the same time. Nevertheless many consumptives describe their cough as very unimportant on account of their innate sorrowless nature, and they will not even be discouraged by the gravest symptoms. Often however it is fear that induces the patients to make light of their coughing, their spitting blood, their losing flesh and to place but little importance on these circumstances. A hoarse cough is a sure sign of a diseased larynx.

Many consumptives complain of cutting pains between the shoulderblades, under the clavicles or in the side; but these are rarely intense and are often entirely wanting. Unfortunately it is unknown to the average layman that the internal organs may suffer extensive tearing down without an indication of pain.The Expectoration of consumptives which is thrown out by coughing with great exertion, is but scant in the beginning, as a rule phlegmy, glassy transparent and sticky. It is one of the suspicious symptoms of developing pulmonary consumption if this lasts for any greater length of time. Sometimes sharply defined, yellowish stripes, at times branching, appear in the same. Later on the expectoration becomes more purulent, and of greenish-yellow or greenish-gray color.

Still later the patients throw out rounded lumps of greenish yellow or yellowish green color, which flatten out like a coin in the spittoon. They sink in water which is a sign of forboding evil.

Blood appears in different quantities in the sputum of consumptives. Bloody streaks are of no importance; they may appear with every violent cough. On the other hand the casting out of pure blood is indeed serious.

The quantity of blood thrown out during an attack may be very different, varying from a few drops hardly a teaspoonful, to hundreds of grammes, even more than a liter. It is generally light red, filled with airbubbles, foamy, and is largely coughed out in coagulated lumps. The coughing of blood is sometimes preceded by a feeling of oppression, rushing of blood to the head and palpitation. Some patients experience a sweet taste in the mouth even before the bleeding. In many cases all preceding symptoms are missing and the patient is suddenly attacked by blood coughing during some more vigorous movement, during the exertion of coughing or even without any direct cause.

Blood coughing seems to appear somewhat more frequently with the female sex than with the male and has with them unmistakable relations to menstruation, as with the sick it often sets in before, often after or even during the same and at such times more frequently than at others.

It is of great importance for the layman to know that a hemorrhage rarely leads to inevitable death. Fatal hemorrhages are always preceded by warning attacks. Blood coughing may appear at any stage of consumption. In some cases it is particularly lasting. Sometimes the patients experience considerable relief from their feeling of oppression after a hemorrhage.

A number of the consumptives as a rule complain of difficulty in deglutition. This is caused by ulcers on the posterior wall of the larynx.

With many patients the appetite is undisturbed for a long time, and there are consumptives that will eat a comparatively large dinner during an attack of fever reaching 40°C. Generally the desire to eat disappears during the course of the disease, especially toward the end of the sickness.The stool may be normal or costive, but is very often diarrhoetic. Twelve or more evacuations may take place during a day; as a rule they are much increased by gasses and are of bad odor. They weaken the patient very much and hasten the end.

One of the most constant attendants during the course of consumption is the Fever. It is rather irregular. In cases of slow process the fever is often very insignificant; often it is only a state of general excitement that takes hold of the patient afternoons, slight dizziness, increased lustre of the eyes, slightly flushed appearance, somewhat increased pulse, which invites to test the temperature of the body by means of a thermometer, which by the way shows it to be about 38°C. With quick consumption the fever is generally high.

Sweat is also a characteristic sign. The exceedingly debilitating effect of night-sweats is well known.

During the course of pulmonary consumption extreme emaciation of the patient is brought about. All tissues are subject to the same, most marked is the disappearance of adipose tissue. This symptom is of the greatest importance as a continued increase in weight means improvement and even cure. Therefore weighing the patient from time to time gives a sure meter for the course of the disease.The course of pulmonary consumption is very different. With quick consumption the end comes within two or three months. Chronic pulmonary consumption may last for years. With this improvements in the fine season alternate with deterioration in the winter.

Concerning the former treatment of pulmonary consumption, this will also be applied in the future in the same manner as far as preventive means and general hygiene is referred to.

For every one will prefer to remain exempt from consumption although it may now be possible to cure those afflicted. The lately published and popularly treated precautionary measures, especially with reference to the expectoration of consumptives retain their full value.

Henceforth the sputum is also to be thrown in a spittoon which is either entirely empty or on account of easier cleansing has the bottom covered with a thin layer of water. It should not be permitted to fill the spittoons with sand or sawdust as the tubercle bacilli can be easily thrown up with the dust.

In the case of a sudden attack of cough a cloth should be held to the mouth to hinder spreading of the fine spray, the same should also be used for wiping the mouth. However the cloth must soon be dampened and cleaned.As bits of the sputum easily stick to the beard especially the moustache overhanging the lips, therefore lung consumptives are advised to wear a short or no beard.

Glasses, spoons, etc. used by consumptives must only be used by other persons after a thorough cleaning with hot water.

The lungdiseased person should abstain from all active and passive kissing, in unavoidable cases kissing should be done on the forehead or cheek only, or hold out those parts only to be kissed. In the same way he should avoid to touch objects with his mouth that may possible be put in the mouth by other persons, especially children, for instance toy-trumpets.

In the case of death from pulmonary consumption, the walls of all rooms and apartments used by the deceased should be rubbed down with fresh baked bread, which is a sure method of removing the bacilli. The bread crumbs that may have dropped on the floor may be removed by a thorough scrubbing with soap, brush and lye.

Upholstered furniture, beds, clothes and wash should be cleaned in a disinfecting place.

Do not wait with precautionary measures till some member of the family has been attacked by pulmonary consumption, but make preparation to prevent the infection while everybody is still sound and healthy.This care ought to begin in a measure with the birth of a child. The same should not be nursed by a mother with diseased lungs nor by a wet-nurse with like affections. Generally wet-nurses are only tested for syphilis; scrofula and tuberculosis receive altogether too little attention.

An important precautionary measure consists in the supervision of the food. The abattoirs and dairies should be placed under the supervision of practical physicians, and the sale of products derived from tuberculous cattle be prohibited. This refers to the milk in the first instance. Tuberculous cows should be excluded from dairy-farms. Raw milk should be avoided as much as possible as boiled milk has the same value.

The meat inspection must be strictly conducted especially with reference to tuberculosis in the case of beef, pork and chickens. Sheep are not subject to tuberculosis.

The associations of children in school and on the play-ground should be watched; do not let them visit in strange families before making thorough investigation as to their sanitary relations.

The health of servant girls should receive greater attention than formerly, as the disease is often carried into the house by them as investigation has proven.In the schools and kindergartens the teacher ought to insist that children do not spit on the floor or in the handkerchief; in case of necessity he should keep sick children out of school and he should especially follow these precautionary measures as regards his own person.

The cleaning of the floor of a room should always be done in a damp way.

Moving into another house it is advised to rub down the walls with fresh baked bread.

As regards societies, every society and every health resort without exception and if possible every hospital should be obliged to have its own apparatus for disinfection and to make extensive use of it. Smaller societies may unite to procure an apparatus of the kind.

Especial attention should be given to the sprinkling of the streets during the dry season.

The state and the larger congregations should make it a point to maintain institutions for consumptives, beyond the city limits if possible, a healthy location in the country preferred.

Every one individually protects himself best from consumption by a methodic habit of washing with cold water, cold rubbing and baths. River and sea baths are generally of excellent results; short shower baths with cool water lasting 20–40 seconds are to be applied later on; they do not only harden the skin but excite deep inhalations and exhalations and in that way act as gymnastics of the lungs. More direct is the action of muscular exercise, such as gymnastics, riding horseback or bicycle, driving, skating, rowing, etc. The carriage of children must be regulated, the drooping forward of their shoulders must be corrected by strengthening the muscles of the back and shoulders by means of dumbbell and other exercises.

All this must still be observed in the future. On the other hand above all the numberless remedies will be dropped that have heretofore been applied as presumably specific remedies for consumption.

Creosote, which was so much praised at its appearance a few years ago and still applied, because of the non-existence of a better remedy, will be dropped into obliteration and with it Guajacol which was just getting to be the "fashion".

All the various inhalation methods that have matured in later years will disappear from the picture plane as far as this has not ever now happened.

The medical remedies, which were given for the torturing cough, for hemorrhage of the lungs, sweats etc., will in most cases be superfluous after this. Hemorrhages will now and then still be experienced as the same may set in unexpectedly.The diatetic cures with whey, koumiss, grapes etc. will retain their importance and also the bathing resorts will be hunted up by patients as formerly.

The owners also of special institutes for curing pulmonary consumption need not despair with the idea that they will not be needed in the future. On the contrary, those needing cure will flock to them in all the greater numbers, as they now know that they certainly will be restored to health within a definitely limited time.