A Living Chemical
Poliomyelitis is caused by a poliovirus. Viruses are particles of either RNA or DNA, and are neither living nor dead. They cannot do anything until they find an appropriate cell whose internal mechanism they can commandeer to start reproducing themselves.
- Karl Landsteiner and Erwin Popper discovered poliovirus in 1908 by proving that it was not a bacterium that caused the paralysis, but a much smaller entity—a virus.
- Viruses are the smallest and simplest infectious agents known… so far.
- Viruses are not cells, but have an attraction (tropism) for receptors on certain cells.
- In addition to polio, RNA viruses include HIV, influenza A, the common cold, hepatitis A and C, yellow fever, rabies, mumps, and measles.
Virology, the study of viruses, started in the 1890s as an offshoot of bacteriology. Viruses were defined primarily by their small size. Size was determined by the virus's ability to pass through a filter such as this porcelain one, and by its invisibility under a light microscope.
Poliomyelitis: Inflammation of the gray matter of the spinal cord. P., acute anterior, acute inflammation of the anterior horns of the gray matter of the spinal cord, leading to a destruction of the large multipolar cells of these horns. It is most common in children, coming on during the period of the first dentition and producing a paralysis of certain muscle groups or of an entire limb.
Gould’s Illustrated Medical Dictionary, 1895
Poliomyelitis: An inflammatory process involving the gray matter of the cord. Acute anterior p., inflammation of the anterior cornua of the spinal cord; an acute infectious disease caused by the poliomyelitis virus and marked by fever, pains, and gastroenteric disturbances, followed by a flaccid paralysis of one or more muscular groups, and later by atrophy.
Stedman’s Medical Dictionary, 1995