KILLING BY RAYS

Waikato Times, Volume 124, Issue 20728, 11 February 1939, Page 15 (Supplement)

KILLING BY RAYS

(A. L., in Prague Press.)

ALL KNOWN FORMS of disinfection have their drawbacks. Boilin'- i an excellent method; but even pasteurised milk must be used up quickly, as otherwise the bacteria remaining in the milk cause oxidation. Yet the taste of the milk would be completely destroyed if so much heat were to be applied to it as to kill all the bacteria is contains. Bacteria-killing chemicals are often poisonous to the human system. Chilling does actually Check the Spread of Bacteria, but it produces such deleterious effects as dampness in meat and spoils its flavour, whilst at the same time doing nothing to check the development of mouldiness of various kinds. There is indeed no kind of degermination which is capable of preventing in any practical way the spread of disease by drinkingglasses and food utensils; neither heating nor even washing with chemical Moreover, up till now no means at all had ever been discovered for applying germ-prevent-ive methods to the air, which is so much the most effective and the quickest means of spreading diseases such as colds, influenza, inflammation of the lungs, infantile paralysis, consumption, psittacosis, etc., and is the greatest conceivable reservoir for all kinds of bacteria and other micro-organisms which cause disease. The fact that the light of the sun, and especially the ultra-violet rays contained therein, can kill or at least enfeeble bacteria is a fact which has been known as long as bacteria themselves. But sunlight contains only a very small range of bactefia-killing rays. The real bactericides, the bacteria-killers, are the ultraviolet rays of essentially short wave-length. The maximum bactericidal effect is found at about 2537 angstroms; but this discovery has only been brought into the light of day from the research work carried out in the past five years by Rentschler and James in the Bloomfield Laboratories of the Westinghouse Company, where the sterilising lamp, as it is called, has now been developed as the first practical discovery for annihilating bacteria by means of ultra-violet light. The sterilising lamp was the Fruit of a Thousand Experiments of this and other kinds, upon which the two scientists and their assistants together expended 50,000 working hours in five years. This lamp has a glow-discharge combined of mercury vapour, argon, neon, etc., which produces hardly any heat and light and very little ozone, but has an ultra-violet radiation very rich in rays of the 2537 angstrom length. The sterilising lamp is strongly made for domestic and professional use, mostly in cylindrical shape. The current consumption is about 10 watts, somewhat less than the average incandescent lamp. The casing is made not from expensive quartz, but of glass—not ordinary glass, but a special kind, the composition of which had first to be discovered. The radiation method required for killing specific bacteria varies considerably. A 75-cm. sterlising lamp at a radus of 10 cm. will kill 95 per cent of all the typhus bacilli contained in clear water in 8 secj onds. As for two other bacteria, botn very dangerous to mankind, the bacterium coli* and the staphy-lococcus, the lamp requires from 23 to 25 seconds in similar conditions. For the black mould-spores, however, it needs 19 minutes. Between these two extremes lies the entire range of the Minute Foes of Mankind living in the air, in water, and in foodstuffs, every one of which has been subjected to “trial by sterilising lamp.” The new lamp has a lifetime of 4000 hours. No complicated technical apparatus had to be called in aid to watch how the death-battle was going under the fatal rays against all these various forms of minute life. A sterilising lamp was fitted to the eye-piece of a microscope, and the microscope picture was thrown upon a piece of linen. Upon a drop of water from some pool being put under the microscope, it was possible to see a collection of slipperanimalculae (paramaecia) and other kinds of known unicellular micro-organisms swimming in lively fashion across the field of virion. Now the lamp is applied. At once the Little Creatures Became Visibly Excited, and their speed was accelerated as they

Check on Bacteria : : Violet-Ray Light

sought to find shelter from the rays. But after a very short time the speed clackened down again and became less and less, until the organisms died. Their bodies swelled up under the effect of the deathrays, blisters were raised on their thin cuticle, the blisters burst, and finally the cells were decomposed and dissolved in the water. In many parts of the United States sterilising lamps are at this very moment in use in various places and for the most varied purposes. Hospitals, banks, petrolstations, druggists’ establishments, restaurants, dairies, farms, factories and ’ households all employ them. In many instances the results are quite remarkable and promising. In the operating theatre, despite all precautions, bacteria falling from the air cause post-operational inflamma’oon, against which every effort of modern asepsis is powerless. Experiments have demonstrated that the dangerous staphylococcus bacilli are made sterile, i.e., powerless, by radiation from the sterilising lamp at a distance of nearly five feet, and died after five minutes. Wounds in animals were subjected to the radiation for a period of from 30 to 90 minutes without any kind of ill consequence. And so operations upon human patients under the sterilising lamp wert initiated, and the Results Were Remarkable. Even in the farthest corners of the operating theatre from 80 per cent to 90 per cent of all the bacteria were killed off, and practically 100 per cent in the air, around the operation scars, and around the instru-ment-tables. The doctors who carried out the experiments reported that infection in the operating theatre had practically ceased, and post-operation temperatures amongst the patients went down markedly. Hitherto, effective sterilisation of drink-ing-glasses and other food utensils was done, for all practical purposes, only by means of super-heated steam. But even really bacteria-free glass can become infected from the air in a few seconds by all kinds of germs. Sterilising lamps are an admirable solution for this otherwise pretty impossible problem, since they can be built into closed receptacles and cupboards for table crockery and glasses—and indeed, as in Washington, have already been so fitted. Germ-disinfection to practically 100 per cent is secured, and can be maintained as long as the lamp is on. Butchers take care to keep their stock in accessible cold-storage rooms. Low temperatures, however, remove the moisture from meat and make its appearance unappetising and the meat itself less tasty. But when sterilising lamps are built into the refrigerators, the temperature can be kept higher—a practical temperature is 10 degrees C. t or 50 degrees F.—and therewith also the moisture-content in the air. This ensures various desirable ends. There is less fluidity lost, and accordingly not so much loss in weight of the meat; the fresh smell and appearance is better maintained, and so is the colour especially; and finally expenses are lower, since the current used by the lamps is much less than would be required for a further reduction in temperature of say, ten down to two degrees Centigrade (50 degrees to 35$ degree F.) Many large canning factories and other foodstuffs businesses have Installed Sterilising Lamps, directly connected with the pipes of their ventilation and air-conditioning systems. The same applies to cosmetic factories, surgical instrument works, breweries and mineral-water plants, and factories for serums. The useful purposes of the lamp are numerous and important. One of the largest factories in the United States use* the Rentschler-James lamp habitually for the irradiation of tooth-pastes and skin foods. There is one bank in the State of New York which has a sterilising lamp fitted above every one of its office windows, so as by this means to reduce as far as possible the spreading of cold germs and other bacilli not merely from one person to another, but among the banknotes. Even lavatory scats have been sterilised in this manner. The procedure, in fact, recalls, a well-known method of fire-preven-tion, since the spreader of bicilli and the endangered property are alike encircled with preventive factors. And here we have fire-prevention by death-rays.