The department of bacteriology, however, is only one of several important features of the institute. One has but to ascend another flight of stairs to pass out of the sphere of the microbe and enter a department where attention is directed to quite another field. We have now come to what may be considered the laboratory of hygiene proper, since here the investigations have to do directly with the functionings of the human body in their relations to the every-day environment. Here again one is struck with the meagre equipment with which important results may be attained by patient and skilled investigators. In only one room does one find a really elaborate piece of apparatus. This exceptional mechanism consists essentially of a cabinet large enough to give comfortable lodgment to a human subject—a cabinet with walls of peculiar structure, partly of glass, and connected by various pipes with sundry mysterious-seeming retorts. This single apparatus, however, is susceptible of being employed for the investigation of an almost endless variety of questions pertaining to the functionings of the human body considered as a working mechanism.
Thus, for example, a human subject to be experimented upon may remain for an indefinite period within this cabinet, occupied in various ways, taking physical exercise, reading, engaged in creative mental labor, or sleeping. Meantime, air is supplied for respiration in measured quantities, and of a precisely determined composition, as regards chemical impurities, moisture, and temperature. The air after passing through the chamber being again analyzed, the exact constituents added to it as waste products of the human machine in action under varying conditions are determined. It will readily be seen that by indefinitely varying the conditions of such experiments a great variety of data may be secured as to the exact physiological accompaniments of various bodily and mental activities. Such data are of manifest importance to the physiologist and pathologist on the one hand, while at the same time having a direct bearing on such eminently practical topics as the construction of shops, auditoriums, and dwellings in reference to light, heat, and ventilation. It remains only for practical architecture to take advantage of the unequivocal data thus placed at its disposal—an opportunity of which practical architecture, in Germany as elsewhere on the Continent, has hitherto been very slow to avail itself.
THE MUSEUM OF HYGIENE
The practical lessons thus given in the laboratory are supplemented in an even more tangible manner, because in a way more accessible to the public, in another department of the institution which occupies a contiguous building, and is known as the Museum of Hygiene. This, unlike the other departments of the institute, is open to the general public on certain days of each week, and it offers a variety of exhibits of distinctly novel character and of high educational value. The general character of the exhibits may be inferred from the name, but perhaps the scope is even wider than might be expected. In a word, it may be said that scarcely anything having to do with practical hygiene has been overlooked. Thus one finds here numberless models of dwelling-houses, showing details of lighting, heating, and ventilation; models not merely of individual dwellings, but also of school-buildings, hospitals, asylums, and even prisons. Sometimes the models represent merely ideal buildings, but more generally they reproduce in miniature actual habitations. In the case of the public buildings, the model usually includes not merely the structures themselves but the surroundings—lawns, drives, trees, out-buildings—so that one can get a very good idea of the more important hospitals, asylums, and prisons of Germany by making a tour of the Museum of Hygiene. Regarding the details of structure, one can actually gain a fuller knowledge in many cases than he could obtain by actual visits to the original institutions themselves.
The same thing is true of various other features of the subjects represented. Thus there is a very elaborate model here exhibited of the famous Berlin system of sewage-disposal. As is well known, the essential features of this system consist of the drainage of sewage into local reservoirs, from which it is forced by pumps, natural drainage not sufficing, to distant fields, where it is distributed through tile pipes laid in a network about a yard beneath the surface of the soil. The fields themselves, thus rendered fertile by the waste products of the city, are cultivated, and yield a rich harvest of vegetables and grains of every variety suitable to the climate. The visitor to this field sees only rich farms and market-gardens under ordinary process of cultivation. The system of pipes by which the land is fertilized is as fully hidden from his view as are, for example, the tributary sewage-pipes beneath the city pavements. The average visitor to Berlin knows nothing, of course, about one or the other, and goes away, as he came, ignorant of the important fact that Berlin has reached a better solution of the great sewage problem than has been attained by any other large city. Such, at least, is likely to be the case unless the sight-seer chance to pay a visit to the Museum of Hygiene, in which case a few minutes' inspection of the model there will make the matter entirely clear to him. It is to be regretted that the authorities of other large cities do not make special visits to Berlin for this purpose; though it should be added that some of them have done so, and that the Berlin system of "canalization" has been adopted in various places in America. But many others might wisely follow their example, notably the Parisians, whose sewerage system, despite the boasted exhibition canal-sewer, is, like so many other things Parisian, of the most primitive character and a reproach to present-day civilization.
It may be added that there are plenty of things exhibited in this museum which the Germans themselves might study to advantage, for it must be understood that the other hygienic conditions pertaining to Berlin are by no means all on a par with the high modern standard of the sewerage system. In the matter of ventilation, for example, one may find admirable models in the museum, showing just how the dwelling and shop and school-room should make provision for a proper supply of pure air for their occupants. But if one goes out from the museum and searches in the actual dwelling or shop or school-room for the counterparts of these models, one will be sorely puzzled where to find them. The general impression which a casual inspection will leave in his mind is that the word ventilation must be as meaningless to the German mind as it is, for example, to the mind of a Frenchman or an Italian. This probably is not quite just, since the German has at least reached the stage of having museum models of ventilated houses, thus proving that the idea does exist, even though latent, in his mental equipment, whereas the other continental nationalities seem not to have reached even this incipient stage of progress. All over Europe the people fear a current of air as if veritable miasm must lurk in it. They seem quite oblivious to any systematic necessity for replenishing the oxygen supply among large assemblies, as any one can testify who has, for example, visited their theatres or schools. And as to the private dwellings, after making them as nearly air-tight as practicable, they endeavor to preserve the status quo as regards air supply seemingly from season to season. They even seem to have passed beyond a mere negative regard for the subject of fresh air, inasmuch as they will bravely assure you that to sleep in a room with an open window will surely subject you to the penalty of inflamed eyes.
In a country like France, where the open fireplace is the usual means employed to modify the temperature (I will not say warm the room), the dwellings do of necessity get a certain amount of ventilation, particularly since the windows are not usually of the best construction. But the German, with his nearly air-tight double windows and his even more nearly sealed tile stove, spends the winter in an atmosphere suggestive of the descriptions that arctic travellers give us of the air in the hut of an Eskimo. It is clear, then, that the models in the Museum of Hygiene have thus far failed of the proselyting purpose for which they were presumably intended. How it has chanced that the inhabitants of the country maintain so high an average of robust health after this open defiance is a subject which the physiological department of the Institute of Hygiene might well investigate.
Even though the implied precepts of the Museum of Hygiene are so largely disregarded, however, it must be admitted that the existence of the museum is a hopeful sign. It is a valuable educational institution, and if its salutary lessons are but slowly accepted by the people, they cannot be altogether without effect. At least the museum proves that there are leaders in science here who have got beyond the range of eighteenth-century thought in matters of practical living, and the sign is hopeful for the future, though its promise will perhaps not be fulfilled in our generation.