Although it has already been suggested that every person who is at all likely to throw light on the subject should be questioned before beginning the examination, the inspector never should accept as a fact any statements that may be made by them; but should always and only depend on the evidence of his own senses.

After having thoroughly studied the surroundings, attention should next be directed to the dwelling. And here at the outset household dirt should be recognized as an important factor in its healthfulness. The dust that accumulates on walls and furniture, and is swept from the floors, would, if sprinkled over the patients in the surgical ward of a hospital, induce such a condition of the wounds as would endanger life. Soiled clothing, sloppails, garbage barrels, the use of the water-closet as a slop-sink, etc., are all sources of foul odors. The inspector must expect discouragement from the inmates when investigating the habits of the family. They will generally try to shield themselves, and will often be quite incensed at the mere suggestion of their being the cause of the trouble, and will censure their landlord or neighbors.

The various points to notice indoors, are:

I. The Dryness of the Air.-This may be judged by the sensation on going suddenly into the cellar. If it is noticeably damp it may come from one of several causes: first, the cellar may be acting like a drain, catching the ground water that flows into it from all sides; second, the rain-water leader may be broken, discharging the water into the ground and allowing it to percolate into the cellar; third, the water-pipes may have burst; fourth, the drain may be broken. During the greater part of the year there is a constant upward current of air in buildings, which creates a partial vacuum in the cellar, sucks in air from the surrounding ground and distributes it through the house. As the cellar air is dry or damp, so will be that of the house; and great care should be taken to discover the cause of any moisture there may be noticed about the walls or floor. A wet and dry bulb hygrometer, such as is used by the Coast Survey, is an admirable instrument for rapid determination of the humidity of air, and of course much more accurate than mere bodily sensation. A humidity of 60, saturation being 100, should be considered the limit for healthy dwellings in this country.

II. The Mode of Heating the Building.-Where hot-air furnaces are used, the position of the air inlet and the condition of the ducts should be carefully examined. Cracks or openings in the fresh-air duct, or the position of the air inlet near a drain opening, or other source of contamination will allow foul air to pass into the heating chamber of the furnace and be distributed through the house.

III. The Means for Ventilation.-As a rule American houses have no other way of changing the air than by opening the windows. Waterclosets oftentimes are found with no connection with the outer air, located in the middle of the house, and what ventilation there is, is into the rooms of the house.

IV. The Plumbing and Drainage.-Unfortunately in most buildings, the pipes are so hidden behind wood-work and under floors, that it is impossible to examine them without calling in carpenters and subjecting the family to great inconvenience. A thorough examination cannot, however, be made without exposing the plumbing to view, and no positive statement of its condition ought to be made on merely a cursory inspection. The plumbing system in any building is very much like a broom, standing on end, with the handle in the cellar. The inspector will therefore, find his work greatly

simplified, by beginning with the trunk lines of pipe and following out the branches, making an off-hand sketch as he goes from floor to floor, showing the positions of the various fixtures, the arrangement of the pipes and their points of junction with each other. Too much care cannot be taken in examining the pipes for imperfect caulking of joints, open connections, putty joints, holes plugged with corks, rag patches, spots of corrosion, and the like.

The fixtures should be examined and their traps tested in order to learn their efficiency as barriers against the entrance of sewer air. To make these tests, as great a pressure should be brought to bear on the traps as there is a possibility of their being subjected to when the plumbing is in constant use. To do this, all the basins, baths, and other fixtures above the traps to be tested and on the same line of piping, should be filled with water and then discharged simultaneously, care being taken that all the pipes are free from obstruction. The fixtures below the trap should then be filled and discharged in the same way. If the trap retains its seal under these tests, it is safe to assume that it is an effectual barrier to the entrance of sewer-air into the building. Every trap should be tested in this way, and a note made of the result.

Pin-holes or air-holes which it is impossible to see with the naked eye, often occur in pipes, and it is therefore best to supplement the examination by a test by which these defects may be detected. For this purpose

some volatile substance, like the oil of peppermint, is used, which being introduced into the piping of a building, finds its way through any defect and is immediately detected by its penetrating odor. To make the test: pour into the top of the pipe, or, if the pipe does not extend through the roof, into the highest fixture, a pailful of boiling water, then half an ounce of the oil, followed by another pail of hot water. The hot water sent down before the oil warms the pipes and prevents the oil from clinging to them. That sent after it tends to volatilize the oil and carry it into every part of the system. Great care should be taken in handling the oil, as a drop will scent the whole building and destroy the test. It is therefore better for two persons to make it; one to handle the oil, and the other to search for traces of it throughout the house. The former should in no case come down into the house until the whole system of piping has been examined by the latter as a very little of the oil on his fingers will impregnate the dwelling. It sometimes becomes necessary to resort to other methods of testing than that by the oil of peppermint, as for instance, when it is impossible to introduce the oil into the pipes without danger of the odor getting out into the house. In such cases the smoke test is sometimes used. While the peppermint is applied at the top, the smoke test is applied at the bottom, and is made by forcing smoke up the drains and pipes by means of a small fan blast. If any imperfections occur in the pipes, the smoke is forced out and is readily detected. The fan should be connected with the pipes at the lowest possible point and before applying the test, all openings known to exist and through which the smoke might be discharged, should be carefully closed.

A list of defects in the plumbing and drainage of houses that have been encountered by a firm of English engineers has been slightly altered to meet American practice, and is given below as being a concise statement of the experience of the writer: 1. Common brick sewers with flat bottoms, under or near houses. 2. Earthen-pipe drains, either broken or with leaky joints, laid under the cellar floor, saturating earth with sewage. 3. Pipe drains, either earthen or iron, laid under houses without sufficient

fall, or with the fall the wrong way. 4. Drains, both earthen and iron, without running traps, admitting air from sewers or cesspools to the pipes in the house. 5. Drains without a free current of air moving constantly through them. 6. Rat-burrows from built drains or sewers undermining flags and floors, and admitting foul air to the house. 7. Rat-burrows worked alongside perfect pipe-drain from street sewers and into houses. 8. Defective connections between soil- or waste-pipes and sewers, admitting foul air to houses. 9. Soil- or waste-pipes without any or sufficient ventilation. 10. Defective water-closet apparatus. 11. Water-closet cisterns with overflows joined to soil-pipe or drain. 12. Safes under closets or basins connected to soil-pipe or drain. 13. Two or more fixtures with unventilated traps on the same line of pipe, siphoning each other when used. 14. Sink overflow-pipes joined to soil-pipes untrapped or with trap liable to siphon. 15. Overflows from basins or baths connected with waste-pipe on sewer side of trap, admitting foul gases to rooms. 16. Water supplies to sinks taken from water-closets or other contaminated cisterns, and used by careless servants for drinking purposes. 17. House cisterns and tanks with overflows direct into soil-pipes or drains. 18. Traps of every description without ample ventilation to prevent them from siphoning. 19. Scullery sinks connected direct to drains admitting foul air to houses, not only through traps, but through joints of brick-work all round, as shown by the smoke test. 20. Bell traps with loose covers on scullery sink connected to drains. 21. Gullies or traps in sculleries, laundries, larders, refrigerators, etc., connected to drains usually dry and untrapped. 22. Rain-leaders used as ventilators to drains, delivering foul air to bed-room windows, or under eaves or roofs. 23. Ash-pits near larders and pantries; ash-pits liable to soak foul moisture through house-walls. 24. Defects of drainage and rat-burrows from neighbors' houses. 25. Water-cisterns in areas near ash-pits or sculleries, and with overflows direct to drains. 26. Wash-basins in dressing-rooms connected directly in any way to drains or soil-pipes. 27. Cisterns of all kinds in houses with overflow connected direct to drains. 28. Cesspools near houses, and cesspools or defective drains near wells. 29. Neighbors' drains crossing under houses, or joining drains.

If an outbreak of contagious or infectious disease is being studied, and up to this point the inspector has not reached any conclusion as to its cause, it would be well for him to examine the food used in common by the families in which the disease occurs. Milk has so often been the carrier of contagion, that everything which in any way could affect it should be carefully examined: the dairy from which it comes, the cows, the milk cans, the water they are washed in, should all receive attention. Then again, the ice may be the cause of the trouble. Impure water in freezing does not make pure ice, and hence the pond or other sources from which it is taken should be examined for any possible cause of contamination.

Many more lines of investigation might be suggested; but space will not admit of their being mentioned. Hundreds of points can only be learned by experience, and all that can be claimed for this article is what its title imports-Some Hints to Sanitary Inspectors.

INDEX.

vitiated by respiration, effects of, i. Amabæ in water, i. 72