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## ANTISEPTICS AND DISINFECTANTS ### PREVENT CATCHING DISEASES **17.5.1 Antiseptics** These are mild chemical substances which, when applied on the body, kill germs. These substances are in such mild concentration that they cause no harm to the skin and body. Lysol, carbolic acid, iodine, benzoic...

## ANTISEPTICS AND DISINFECTANTS ### PREVENT CATCHING DISEASES **17.5.1 Antiseptics** These are mild chemical substances which, when applied on the body, kill germs. These substances are in such mild concentration that they cause no harm to the skin and body. Lysol, carbolic acid, iodine, benzoic acid, mercurochrome, boric acid, etc., in dilute solution are good antiseptics. Certain antibiotic creams also serve the same purpose. **A CAUTION** Do not use commercial names as examples of antiseptics in your examination answers. Names like Dettol, Savlon, Listerine, Soframycin are all commercial names. They may have one or the other active ingredient individually or in combination. It is the active ingredients which actually serve as antiseptics. **17.5.2 Disinfectants** These are strong chemical substances that are applied on spots and places where germs thrive and multiply. Commonly used disinfectants are cresol, phenol, lysol, 40% formalin, lime, bordeaux mixture, DDT, etc. Precaution: All disinfectants are strong and should not come in contact with the human skin. Strong heat and boiling also destroy germs and may be called physical disinfectants. ## ANTITOXINS (More appropriately called antibodies) **The terms "Toxin" and "Antitoxin".** Toxin is a general term used for any poisonous substance produced by an animal or a plant or a bacterium. Example: Snake venom, sting poisons of scorpions, insects, etc., or even poisonous chemicals released by pathogens growing inside the body. "Antitoxin" was the name given to any chemical substance produced inside the body in response to the entry of foreign poisonous substance. "Antivenins" for snake bites are produced inside animals like horses. Presently, the more general term "antibody" is used instead of "antitoxin", "Antibody" is a blood serum protein produced in response to the injected antigens. ## ANTIBIOTICS ## **OTHERS** Antibiotics are chemical substances that can kill other microorganisms. **The term ANTIBIOTIC** The first antibiotic was discovered in 1929, but its first use was tried in the 1940s. Such category of drugs was discovered by Selman Waksman in 1943. **DISCOVERY OF FIRST ANTIBIOTIC ** Alexander Fleming, a scientist at a hospital in London, observed a bacterium Staphylococcus growing in clusters in a petri dish but also noticed an unwanted mould _Penicillium notatum_ in the cultures in a petri dish, inhibiting the growth of the bacterium. Obviously, some substance was released from the mould, which killed the bacteria at some distance. Fleming called this substance released by the mould, penicillin. He successfully experimented with this substance in 1929. In the experiment this substance proved an effective killer for bacteria. The experiment was tried on laboratory animals and human beings, and good results were obtained without harming any organism. On humans, penicillin was successfully tried in the early 1940s against several infections and the results were good in its use.