Science and Medicine

Entries - Entry Category: Science and Medicine - Starting with V

Vaccination

Vaccination artificially increases immunity to disease and contributes to the development of herd immunity, which is achieved when a sufficiently large percentage of immunized individuals  reduces the likelihood of disease transmission. Beginning in the nineteenth century, vaccination became an essential part of American public health policy. In Arkansas, starting with the introduction of school smallpox vaccination requirements in the late nineteenth century, vaccination became a vital feature of modern public health policy. The smallpox vaccine, discovered by British physician Edward Jenner in 1796, was the world’s first vaccine and remained the only human vaccine available until 1885. Following the introduction of the smallpox vaccine into the United States in 1800, Massachusetts became the first state to mandate smallpox vaccinations, requiring …

Venomous Snakes

Arkansas hosts about forty-five species and subspecies of snakes, and six (thirteen percent) are species that use venom to obtain food and to defend themselves. There are two families of venomous snakes in the state: Elapidae (a single elapid species, the Texas coral snake) and Viperidae (five species of pitvipers). All of Arkansas’s venomous snakes inject venom through fangs via muscular contraction of paired venom glands. Texas Coral Snake The Texas coral snake, Micrurus tener tener (formerly Micrurus fulvius tenere) is a tricolored, medium-sized (maximum length = 122 centimeters), secretive elapid snake that primarily occurs in the southern and southwestern part of the state. Verified records are available for only five counties of the state in the Gulf Coastal Plain, …

Vines

In 2016, a total of 436 kinds of woody plants were known to occur in the wild in Arkansas, comprising 419 species plus another seventeen varieties and subspecies. Of these, 185 can be considered trees, 189 are best described as shrubs, and sixty-two are woody vines. In some cases, it is difficult to draw a hard line between these categories, and various reference works differ in their criteria for each. For the purposes of this entry, however, each category is defined as follows: Trees are defined as perennial, often single- or relatively few–stemmed woody plants typically greater than five meters (sixteen feet) in height at maturity. Shrubs are defined as perennial, often multi-stemmed woody or semi-woody plants usually less than …