History of "Soap"

 The invention of soap dates back to ancient times, and it is challenging to pinpoint a specific individual or culture responsible for its discovery. The use of soap-like substances for cleaning has been traced back to various ancient civilizations.

Ancient Babylonians are believed to have been using a soap-like substance around 2800 BCE. They combined fats, water, and ashes to create a cleaning product. Similarly, ancient Egyptians used a mixture of animal and vegetable oils with alkaline salts to produce a soap-like substance for washing.

The Greeks and Romans also had various forms of soap, but they often used it more for medicinal and cosmetic purposes than for cleansing the body. The word "soap" is derived from the Celtic word "saipo" and the Latin word "sāpō," both of which mean "soap."

Throughout history, soap production methods evolved, and different cultures contributed to its development. However, the widespread use of soap for personal hygiene became more common in Europe during the Middle Ages.

In the 19th century, with advancements in chemistry, soap production underwent significant improvements. The introduction of synthetic ingredients and industrial processes helped make soap more widely available and affordable.

In summary, the invention of soap is a result of a long historical process, with contributions from various civilizations and cultures over thousands of years. It evolved from simple mixtures of fats and alkaline substances to the diverse range of soaps we have today.

What is the skin colour of Polar Bear?

Polar bears' fur consists of a dense, insulating underfur topped by guard hairs of various lengths. It is not actually white — it just looks like white. Each hair shaft is pigment-free, transparent with a hollow core that scatters and reflects visible light, much like what happens with ice and snow. Polar bears look whitest when they are clean and in high angle sunlight, especially just after the they shed old hair or skin to make way for a new growth, which usually begins in spring and is complete by late summer. Before shedding their old hair or skin, accumulated oils in their fur from the seals they eat can make them look yellow.

What causes leprosy?

Leprosy was recognized in the ancient civilizations of China, Egypt and India. The first known written mention of Leprosy is dated 600 BC. Throughout history, people affected with have often been ostracized by their communities and families.Leprosy, also named as  Hansen's disease HD, is caused by certain bacteria called Mycobacterium leprae bacillus. The disease takes its name from the Latin word Lepra, which means "scaly", while the term "Hansen's disease" is named after the physician Gerhard Armauer Hansen.  The bacterial attack the skin and nervous system, causing lumps and patches of dis-colouration on the skin of the individual.  Intially the infections are without any visible symptons and typically remain this ways for 5 years and as long as upto  20 years. Thereafter symptoms start developing on skin, on ears, fce, testes and the limps, inner surface of the mouth and nose. When the disease spreads to the eyes, it causes blindness. The diseases also affects, nerves, respiratory tract and this result in lack of ability to feel pain and thus loss of parts of extremities due to repeated injuries.Leprosy is mainly of two types – Lepromatous or Cutaneous and Tuberculoid. Lepromatous is marked by wide spread infiltration of grainy masses of inflamed tissue under the skin, face, testes and mucosal membranes of the upper respiratory tract. But the Tuberculoid is marked by stain like lesions with raised, reddist borders and patches that become insensitive to physical stimulous as they spread.  Amongst the main symptoms of the disease are thickening of he skin, loss of hair, deformities of bones and joints and loss of sensation in various areas of the body.Leprosy is curable with treatment. Treatment for paucibacillary leprosy is with the medications - dapsone and rifampicin.  Treatment for multibacillary leprosy consists of rifampicin, dapsone, and clofazimine.  A number of other antibiotics may also be used for its treatment.WHO figures says that official figures from 115 countries show the global registered prevalence of leprosy at 189018 at the end of 2012 and during the same year, 232 857 new cases were reported.

How does scratching stop itching.

Itching is a funny phenomena. It is the direct result of damage to cells in our skin. As a result of the damage, substances like histamine  (the amine that causes widening of blood vessels and plays a role in allergic phenomena) are set free which, like any other free item. The signals of this irritation, skin to how pain signals are sent, are sent to the central nervous system.

One can compare the nerve fibres to telephone lines and the central nervous system to a switchboard. The switch-board routes incoming telephone calls and makes sure that only one like at a time is  connected with each telephone number, Unlike the telephone lines, which sometimes get jumpled up, the nerve signals move on exclusive lines.

By occupying the line you can prevent others from having a conversation with the same number. Similarly, the itch message can be blocked by occupying the central nervous system with another signal, for example one generated by scratching. If another less irritating activity can substitute for itching, the problem goes away on its own.