Studies that are in vivo (Latin for “within the living”; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms usually animals including humans, and plants as opposed to a partial or dead organism, or those done in vitro (“within the glass”), i.e., in a laboratory environment using test tubes, petri dishes etc. Examples of investigations in vivo include: the pathogenesis of disease by comparing the effects of bacterial infection with the effects of purified bacterial toxins; the development of antibiotics, antiviral drugs, and new drugs generally; and new surgical procedures. Consequently animal testing and clinical trials are major elements of in vivo research. In vivo testing is often employed over in vitro because it is better suited for observing the overall effects of an experiment on a living subject. The English microbiologist Professor Harry Smith and his colleagues in the mid-1950s showed the importance of in vivo studies. They found that sterile filtrates of serum from animals infected with Bacillus anthracis were lethal for other animals, whereas extracts of culture fluid from the same organism grown in vitro were not. This discovery of anthrax toxin through the use of in vivo experiments had a major impact on studies of the pathogenesis of infectious disease. The maxim in vivo veritas (“in a living thing [there is] truth”) is used to describe this type of testing and is a play on in vino veritas, (“in wine [there is] truth”) a well-known proverb.
by MyBiosource Editorial Team | Feb 16, 2023