DISINFECTION. — In disinfecting a room the doors, windows, etc., must be made perfectly tight, as the diffusive power of the gas is very high. The gas may be generated outside the room in one of the various generators to be had, and the gas conducted by a tube through the key-hole. Some forms of apparatuses are operated within the apartment. After a sufficient amount of gas has been set free in the apartment, it is left for twenty-four hours. Length of exposure appears to be secondary to the quantity of gas used. An excess is recommended by most authorities.
Superficial instruments, bed-pans, urinals, bedding, surgical dressings may be sterilized in small closets or in suit able receptacles. Formaldehyde does not seem to affect the coloring matter of the wall-paper, drapery, or garments (except light shades of violet and light red), and for this reason it is preferable to chlorine as a disinfectant for apartments. After the disinfection is completed the rooms should be aired for some hours, as the gas is very irritating to the throat and eyes.
The various lamps are too small and give uncertain results. Two methods proved to be highly effective against the various bacteria with which rooms were infected: One by spraying the walls, furniture, etc., with a 2-per-cent. solu tion and allowing the room to remain closed for twenty-four hours; 60 to 70 cubic centimetres of solution are enough for a square metre of surface. The other by evaporation from sheets dipped into a solution of half a kilogramme of calcium chloride in a litre of formalde hyde and hung in the room. The room is left closed until the next day. A sheet of two square metres is enough for eight cubic metres of space. The method by spraying is a very cheap process, but those engaged in the work must protect the eyes by a special form of glasses and the hands with gloves or vaselin, and must use a cotton-wool respirator. Nils Englund ("Om Formal dehyden," Stockholm, '95).
Pastils made of the solid polymerized formaldehyde (trioxymethylcne) recom mended. Each pastil weighs 1 gramme, and contains 100 per cent. formaldehyde,
which is evolved by heating on a quite simple apparatus. After carefully clos ing all crevices in the room, the lamp of the apparatus is lit, and then the door closed. By burning one pastil for each cubic metre of room space, the author found that all non-spore-bearing organisms placed in any part of.' the room were killed after twenty-four hours. Aronson (Zeit. f. Hyg., Leipzig, B. 25, H. 1).
Fresh and dry tubercle bacilli are killed with comparative ease, but, on the whole, the agent is not well suited to general disinfection. Many difficulties present themselves, many lamps are needed, and the agent is a bad one for handling. It cannot be used in a coin pressed form in cylinders, since it goes from monoformaldehyde into tri-, hexa-, and other higher polymers, which are indifferent bodies, hardly to be con sidered as disinfectants. E. Pfuhl (Zeit. f. Hygiene u. Infects., xxii, 339).
New lamp for disinfecting-purposes, consisting of a disk of moderately thick asbestos-board perforated with small holes close together and platinized with a strong solution of platinic chloride, and a lamp-font, which is a shallow, cylindrical dish of such size that the disk will just cover the top. This font is partly filled with methyl-alcohol. The disk is wet with the alcohol and re moved from the dish, and then the alco hol is ignited. By the time the alcohol burns away the disk is sufficiently heated so that when placed over the lamp-font again it will continue hot and change the alcohol to the aldehyde most efficiently. The amount of alcohol con verted in a given time depends on the size of the disk; with one of six inches' diameter a litre can be converted in an hour.
At least a quart of alcohol should be used in disinfecting an ordinary living room; this amount will yield about thirty-six volumes of the aldehyde-gas, which, as such, or in solution, is practi cally without injurious effect on metals, wood, cloth, and most colors. F. C. Robinson (Jour. of Amer. Public Health Assoc., Oct., '96).