Medicine: What Is It?

Six big U.S. pharmaceutical firms* are now producing Salk vaccine or hurrying to get into production. The vaccine works on a principle that has already provided protection against such traditional plagues as smallpox and yellow fever. When they attack human beings or other mammals, most viruses stimulate the invaded system to manufacture tiny protein particles "called antibodies. If the system under assault does not have enough of these antibodies, or cannot manufacture them fast enough, the victim may die, or, with polio, suffer permanent crippling. Polio virus is unusual in that there are three main types. All can...