Sunday, July 8, 2018
First of all what are vaccines? Vaccines are substances used to produce immunity to diseases in the living body. Immunity is the ability of the body to resist a diseases by natural or artificial means.
Smallpox vaccine, the first successful vaccine to be developed, was introduced by Edward Jenner in 1796. He followed up his observation that milkmaids who had previously caught cow pox did not later catch smallpox by showing that inoculated cowpox protected against inoculated smallpox. The word "vaccine" is derived from Variolae vaccinae (i.e. smallpox of the cow), the term devised by Jenner to denote cowpox and used in the long title of his An enquiry into the causes and effects of Variolae vaccinae, known by the name of cow pox.Vaccination, the term which soon replaced cowpox inoculation and vaccine inoculation, was first used in print by Jenner's friend, Richard Dunning in 1800.[3] Initially, the terms vaccine/vaccination referred only to smallpox, but in 1881 Louis Pasteur proposed that to honor Jenner the terms be widened to cover the new protective inoculations being introduced.
What is friction?
The resistance that one surface or object encounters when moving over another.a lubrication system which reduces friction’ It's or...
